Becoming an Android Librarian (Android World Wide 2023 Jan)

Becoming an Android Librarian (Android World Wide 2023 Jan)

Transcript

1. G E T S T R E A M . I O
   Becoming an
   Android Librarian
   

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2. G E T S T R E A M . I O
   skydoves
   @github_skydoves
   Android Developer Advocate @ Stream
   Jaewoong Eum
   

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3. G E T S T R E A M . I O
   Open-Source Libraries
   

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4. G E T S T R E A M . I O
   Open-Source Libraries
   

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5. G E T S T R E A M . I O
   Library & SDK Lifecycles
   Design
   Develop
   Prepare
   Release
   

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6. G E T S T R E A M . I O
   Library & SDK Lifecycles
   Design
   Develop
   Prepare
   Release
   Design process
   

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7. G E T S T R E A M . I O
   Library & SDK Lifecycles Design process
   1. Define a problem
   2. Research overall ideas
   3. Verify the feasibility of your ideas
   4. Investigate dependencies
   5. Draw blueprints of application interfaces
   6. Design the application interfaces
   

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8. G E T S T R E A M . I O
   Library & SDK Lifecycles
   Design
   Develop
   Prepare
   Release
   Development strategies
   

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9. G E T S T R E A M . I O
   Development Strategies Minimize API surfaces
   Module
   Public
   Interface
   

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10. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Client
    Client
    Client
    Client
    

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11. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Client
    Client
    Client
    Client
    

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12. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Client
    Client
    Client
    Client
    

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13. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Public
    Internal
    

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14. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Client
    Client
    Client
    Client
    Public
    Internal
    

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15. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Client
    Client
    Client
    Client
    

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16. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Client
    Client
    Client
    Client
    

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17. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    private internal
    importance
    protected public
    

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18. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    private internal
    importance
    protected public Client
    Client
    Client
    

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19. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    class ApiResponseCallAdapter constructor(
    val resultType: Type
    ) : CallAdapter>> {
    override fun responseType(): Type {
    return resultType
    }
    override fun adapt(call: Call): Call> {
    return ApiResponseCallDelegate(call)
    }
    }
    Client
    

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20. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    internal class ApiResponseCallAdapter constructor(
    private val resultType: Type
    ) : CallAdapter>> {
    override fun responseType(): Type {
    return resultType
    }
    override fun adapt(call: Call): Call> {
    return ApiResponseCallDelegate(call)
    }
    }
    Client
    

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21. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    fun Context.dp2Px(dp: Int): Int {
    val scale = resources.displayMetrics.density
    return (dp * scale).toInt()
    }
    fun Context.px2Sp(px: Int): Int {
    val scale = resources.displayMetrics.scaledDensity
    return (px / scale).toInt()
    }
    val px = context.dp2Px(dp = 22)
    val sp = context.px2Sp(px = 22)
    

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22. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    internal fun Context.dp2Px(dp: Int): Int {
    val scale = resources.displayMetrics.density
    return (dp * scale).toInt()
    }
    internal fun Context.px2Sp(px: Int): Int {
    val scale = resources.displayMetrics.scaledDensity
    return (px / scale).toInt()
    }
    val px = context.dp2Px(dp = 22) // Unresolved reference
    val sp = context.px2Sp(px = 22) // Unresolved reference
    

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23. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    internal fun Context.dp2Px(dp: Int): Int {
    val scale = resources.displayMetrics.density
    return (dp * scale).toInt()
    }
    internal fun Context.px2Sp(px: Int): Int {
    val scale = resources.displayMetrics.scaledDensity
    return (px / scale).toInt()
    }
    int px = ContextExtensionKt.dp2Px(context, 11);
    int sp = ContextExtensionKt.px2Sp(context, 11);
    

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24. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    @JvmSynthetic
    internal fun Context.dp2Px(dp: Int): Int {
    val scale = resources.displayMetrics.density
    return (dp * scale).toInt()
    }
    @JvmSynthetic
    internal fun Context.px2Sp(px: Int): Int {
    val scale = resources.displayMetrics.scaledDensity
    return (px / scale).toInt()
    }
    int px = ContextExtensionKt.dp2Px(context, 11); // Unresolved reference
    int sp = ContextExtensionKt.px2Sp(context, 11); // Unresolved reference
    

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25. G E T S T R E A M . I O
    Development Strategies Explicit API mode
    

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26. G E T S T R E A M . I O
    Development Strategies Explicit API mode
    

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27. G E T S T R E A M . I O
    Development Strategies Explicit API mode
    

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28. G E T S T R E A M . I O
    Development Strategies Explicit API mode
    

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29. G E T S T R E A M . I O
    Development Strategies Explicit API mode
    

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30. G E T S T R E A M . I O
    Development Strategies Binary Compatibility Validator
    

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31. G E T S T R E A M . I O
    Development Strategies Binary Compatibility Validator
    build.gradle
    module.gradle
    On terminal
    

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32. G E T S T R E A M . I O
    Development Strategies Binary Compatibility Validator
    module.api
    

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33. G E T S T R E A M . I O
    Development Strategies Binary Compatibility Validator
    

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34. G E T S T R E A M . I O
    Development Strategies Metalava
    

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35. G E T S T R E A M . I O
    Development Strategies Exposing resources
    /classes.jar
    /res/
    /R.txt
    /public.txt
    /assets/
    /libs/name.jar
    /jni/abi_name/name.so
    /proguard.txt
    /lint.jar
    /api.jar
    AAR file
    

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36. G E T S T R E A M . I O
    Development Strategies Exposing resources
    /classes.jar
    /res/
    /R.txt
    /public.txt
    /assets/
    /libs/name.jar
    /jni/abi_name/name.so
    /proguard.txt
    /lint.jar
    /api.jar
    AAR file
    res/drawable
    res/layout
    res/menu
    res/values
    res/xml
    res/raw
    res/anim
    res/animator
    res/mipmap
    res/font
    string.xml
    colors.xml
    styles.xml
    dimens.xml
    arrays.xml
    …
    /res/
    /res/values/
    

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37. G E T S T R E A M . I O
    Development Strategies Exposing resources
    
    #FFFFFF
    #000000
    #57A8D8
    #FBC02D
    
    Library (colors.xml) Project
    val whiteColor = ContextCompat.getColor(this, R.color.white)
    binding.myView.setBackgroundColor(whiteColor)
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:text="skydoves"
    android:textColor="@color/yellow" />
    

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38. G E T S T R E A M . I O
    Development Strategies Exposing resources
    
    #FFFFFF
    #000000
    #57A8D8
    #FBC02D
    
    Library (colors.xml)
    val whiteColor = ContextCompat.getColor(this, R.color.white)
    binding.myView.setBackgroundColor(whiteColor)
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:text="skydoves"
    android:textColor="@color/yellow" />
    Project compile error!
    

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39. G E T S T R E A M . I O
    Development Strategies Exposing resources
    
    

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40. G E T S T R E A M . I O
    Development Strategies Exposing resources
    
    
    

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41. G E T S T R E A M . I O
    Development Strategies Exposing resources
    
    
    

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42. G E T S T R E A M . I O
    Development Strategies Exposing resources
    Project (XML) Project (code)
    

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43. G E T S T R E A M . I O
    Development Strategies Exposing resources
    Project (XML) Project (code)
    

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44. G E T S T R E A M . I O
    Development Strategies Exposing resources
    

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45. G E T S T R E A M . I O
    Development Strategies Exposing resources
    

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46. G E T S T R E A M . I O
    Development Strategies Exposing resources
    Library (layout_balloon.xml) Library (Balloon.Builder.kt)
    

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47. G E T S T R E A M . I O
    Development Strategies Exposing resources
    ● Some issues have been reported in Crashlytics.
    ● But the reports were not helpful at all.
    ● Occasionally the library behaves very weirdly.
    ● Also it’s really difficult to reproduce.
    

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48. G E T S T R E A M . I O
    Development Strategies Exposing resources
    Perhaps..?
    

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49. G E T S T R E A M . I O
    Development Strategies Exposing resources
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:clipChildren="false"
    android:clipToPadding="false"
    android:padding="10dp">
    android:id="@+id/text"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center_vertical"
    android:textColor="@android:color/white" />
    …
    Library (layout_balloon.xml) Project (layout_balloon.xml)
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:clipChildren="false"
    android:clipToPadding="false"
    android:padding="10dp">
    android:id="@+id/text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="12dp"
    android:text="skydoves"
    android:textSize="16sp"
    android:textStyle="bold" />
    ...
    

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50. G E T S T R E A M . I O
    Development Strategies Exposing resources
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:clipChildren="false"
    android:clipToPadding="false"
    android:padding="10dp">
    android:id="@+id/text"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center_vertical"
    android:textColor="@android:color/white" />
    …
    Library (layout_balloon.xml)
    // wrong behaviors
    Project (layout_balloon.xml) // runtime error!
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:clipChildren="false"
    android:clipToPadding="false"
    android:padding="10dp">
    android:id="@+id/text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="12dp"
    android:text="skydoves"
    android:textSize="16sp"
    android:textStyle="bold" />
    ...
    

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51. G E T S T R E A M . I O
    Development Strategies Resource prefix
    resourcePrefix
    

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52. G E T S T R E A M . I O
    Development Strategies Resource prefix
    resourcePrefix
    

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53. G E T S T R E A M . I O
    Development Strategies Resource prefix
    build.gradle
    

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54. G E T S T R E A M . I O
    Development Strategies Resource prefix
    layout_balloon.xml attrs.xml
    

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55. G E T S T R E A M . I O
    Development Strategies Resource prefix
    

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56. G E T S T R E A M . I O
    Development Strategies
    R class
    Non transitive R class
    

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57. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    

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58. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    

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59. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library :material (MDC)
    implementation implementation
    

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60. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library :material (MDC)
    com.google.android.material.R
    (:material)
    implementation implementation
    

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61. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library :material (MDC)
    com.my.library.R
    (:material)
    (:library)
    com.google.android.material.R
    (:material)
    implementation implementation
    

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62. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library :material (MDC)
    com.my.library.R
    (:material)
    (:library)
    com.google.android.material.R
    (:material)
    com.my.app.R
    (:material)
    (:library)
    (:app)
    implementation implementation
    

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63. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library :material (MDC)
    Transitive dependency
    com.my.library.R
    (:material)
    (:library)
    com.google.android.material.R
    (:material)
    com.my.app.R
    (:material)
    (:library)
    (:app)
    implementation implementation
    

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64. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    com.my.library.R
    (:material)
    (:library)
    

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65. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    

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66. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library :material (MDC)
    implementation implementation
    com.my.library.R
    (:material)
    (:library)
    com.google.android.material.R
    (:material)
    com.my.app.R
    (:material)
    (:library)
    (:app)
    Wow, a million of LoC in R classes in a minute!
    

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67. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    Dex format has 64K limit for methods and fields references!
    64K (65,536 = 64 x 1024 (2^10))
    

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68. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    

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69. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    android.nonTransitiveRClass=true
    gradle.properties
    

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70. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library
    implementation implementation
    com.my.library.R
    (:library)
    com.google.android.material.R
    (:material)
    com.my.app.R
    (:app)
    Refer to its own resources without pulling resources from dependencies.
    nonTransitiveRclass
    :material (MDC)
    

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71. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    Before After (enabled non transitive R class)
    

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72. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    aar size diff
    226054 bytes -> 214538 bytes (11516 bytes reduced)
    10,000 end-users
    2260540000 bytes -> 2145380000 bytes (≈115 MB reduced)
    100,000 end-users
    22605400000 bytes -> 21453800000 bytes (≈1.1 GB reduced)
    1,000,000 end-users
    226054000000 bytes -> 214538000000 bytes (≈10 GB reduced)
    100,000,000 end-users
    22605400000000 bytes -> 21453800000000 bytes (≈1 TB reduced)
    

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73. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app
    :feature1
    :feature2
    :feature3
    com.my.app.R
    (:feature1)
    (:feature2)
    (:feature3)
    (:app)
    Unresolved reference
    

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74. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app
    :feature1
    :feature2
    :feature3
    com.my.app.R
    (:feature1)
    (:feature2)
    (:feature3)
    (:app)
    full name package
    import with namespacing
    

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75. G E T S T R E A M . I O
    Library & SDK Lifecycles
    Design
    Develop
    Prepare
    Release
    

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76. G E T S T R E A M . I O
    Preparation Documentation (KDoc)
    

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77. G E T S T R E A M . I O
    Preparation Documentation (Dokka)
    ./gradlew dokkaHtml
    ./gradlew dokkaHtmlMultiModule
    ./gradlew dokkaJavadoc
    

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78. G E T S T R E A M . I O
    Preparation Documentation (README)
    

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79. G E T S T R E A M . I O
    Library & SDK Lifecycles
    Design
    Develop
    Prepare
    Release
    

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80. G E T S T R E A M . I O
    Release Maven
    

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81. G E T S T R E A M . I O
    Release Maven repositories
    mavenCentral()
    google()
    jcenter()
    

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82. G E T S T R E A M . I O
    Release Maven central repository
    1. Registering a Sonatype account
    2. Generating a GPG key pair
    3. Setting up publication in your project
    a. Maven publishing setup with Gradle
    b. Signing artifacts with GPG key
    c. Configure pom files
    d. Per-module Gradle setup
    4. Publish to sonatype repository
    5. Evaluate and close the ticket on staging
    repositories
    

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83. G E T S T R E A M . I O
    Release Maven central repository
    🔗 https://bit.ly/386yJt1
    

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84. G E T S T R E A M . I O
    Release Jitpack
    maven { url 'https://jitpack.io' }
    

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85. G E T S T R E A M . I O
    Library & SDK Lifecycles
    Design
    Develop
    Prepare
    Release
    Verification
    

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86. G E T S T R E A M . I O
    Verifying and Marketing Community
    

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87. G E T S T R E A M . I O
    Verifying and Marketing Technical contents
    

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88. G E T S T R E A M . I O
    Verifying and Marketing Example projects
    Codes speak louder than words!
    

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89. G E T S T R E A M . I O
    Blog Post
    🔗 https://bit.ly/3Qim5ZB
    

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90. G E T S T R E A M . I O
    https://github.com/skydoves
    jaewoong.eum@getstream.io
    https://twitter.com/github_skydoves
    https://medium.com/@skydoves
    Contact
    

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91. G E T S T R E A M . I O
    Thank you.
    

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