feat: Add InternalUsageAttributionId documentation and opt out (#747)

* feat: Add InternalUsageAttributionId documentation and opt out

This change adds documentation about the InternalUsageAttributionId and provides a means for the user to disable the
attribution id.

* feat: Moves attribution ID comments to the calling function kdoc

* chore: more explanation for when to set the attributionId value.

* docs: move internal usage attribution ID section

Author: dkhawk

README.md

@@ -497,6 +497,13 @@ Box(Modifier.fillMaxSize()) {
 
 The colors of the text, line, and shadow are also all configurable (e.g., based on `isSystemInDarkTheme()` on a dark map). Similarly, the `DisappearingScaleBar` animations can be configured.
 
+## Internal usage attribution ID
+
+This library calls the MapsApiSettings.addInternalUsageAttributionId method, which helps Google
+understand which libraries and samples are helpful to developers and is optional. Instructions for
+opting out of the identifier are provided in
+[reference documentation](maps-compose/src/main/java/com/google/maps/android/compose/internal/MapsApiAttribution.kt).
+
 ## Contributing
 
 Contributions are welcome and encouraged! If you'd like to contribute, send us a [pull request] and refer to our [code of conduct] and [contributing guide].

maps-compose/src/main/java/com/google/maps/android/compose/internal/MapsApiAttribution.kt

@@ -20,16 +20,30 @@ internal object MapsApiAttribution {
     private val _isInitialized = mutableStateOf(false)
     val isInitialized: State<Boolean> = _isInitialized
 
+    /**
+     * The value of the attribution ID.  Set this to the empty string to opt out of attribution.
+     *
+     * This must be set before calling the GoogleMap composable.
+     */
+    var attributionId: String = AttributionId.VALUE
+
     /**
      * Adds the attribution ID to the Maps API settings. This is done on a background thread
      * using [Dispatchers.IO]. The attribution ID is only added once.
      *
+     * Adds a usage attribution ID to the initializer, which helps Google understand which libraries
+     * and samples are helpful to developers, such as usage of this library.
+     * To opt out of sending the usage attribution ID, it is safe to delete this function call
+     * or replace the value with an empty string.
+     *
+     * See https://developers.google.com/android/reference/com/google/android/gms/maps/MapsApiSettings#addInternalUsageAttributionId(android.content.Context,%20java.lang.String)
+     *
      * @param context The context to use to add the attribution ID.
      */
     suspend fun addAttributionId(context: Context) {
         if (hasBeenCalled.compareAndSet(false, true)) {
             withContext(Dispatchers.IO) {
-                MapsApiSettings.addInternalUsageAttributionId(context, AttributionId.VALUE)
+                MapsApiSettings.addInternalUsageAttributionId(context, attributionId)
                 _isInitialized.value = true
             }
         }