Adds peer-to-peer (P2P) mesh synchronization between ObjectBox Sync clients on Android, without a central server, using Google Nearby Connections.

This is a plain (no native code, single variant) Android library that apps add in addition to the Sync variant of the ObjectBox Android library (e.g. objectbox-sync-android), which contains the native mesh sync implementation. Keeping it separate avoids multiplying the variants of the main Android library (basic/sync × with/without Admin) and keeps the Nearby dependency out of apps that don't use mesh sync.

What this library provides:

• AndroidMeshSync.createConfig(context, meshId) creating a MeshConfig (see objectbox-java) with the Nearby Connections mesh network attached, to pass to SyncBuilder.mesh().
• The permissions that may be required by Nearby Connections, merged into the app manifest (see AndroidManifest.xml).
• The play-services-nearby dependency.

Note that not all permissions this library adds may be required. Depending on a device's Android SDK version and your app's needs, only some of them may actually be necessary. For example, location permissions are typically not required for Nearby Connections on recent Android releases.

To remove them as needed, use merge rule markers in your app's manifest, for example:

<uses-permission
    android:name="android.permission.ACCESS_COARSE_LOCATION"
    tools:node="remove" />
<uses-permission
    android:name="android.permission.ACCESS_FINE_LOCATION"
    tools:node="remove" />

Also note that your app must request any dangerous (runtime) permissions at runtime when needed. This library provides a MeshSyncPermissions helper class to request the permissions included by default.

val meshConfig: MeshConfig = AndroidMeshSync.createConfig(context, "example.myapp.mesh")

val syncClient: SyncClient = Sync.client(boxStore)
        .url(SYNC_SERVER_URL)
        .credentials(credentials)
        .mesh(meshConfig)
        .buildAndStart()

val mesh: MeshSync? = syncClient.getMesh() // state, connected peer count, stats