title: gRPC fails when service method called from Android SyncAdapter
body: <p>It took me some time to figure out that below error is caused only when I try to use gRPC client from SyncAdapter:</p>
  
  <pre><code>No functional channel service provider found. Try adding a dependency on the grpc-okhttp or grpc-netty artifact
  </code></pre>
  
  <p>The setup is exactly like in official tutorial <a href="http://developer.android.com/training/sync-adapters/index.html" rel="noreferrer">Transferring Data Using Sync Adapters</a>.</p>
  
  <p>I've generated gRPC code using same setup as an <a href="https://github.com/grpc/grpc-java/tree/master/examples/android" rel="noreferrer">example</a> from grpc-java. The <code>compile 'com.squareup.okhttp:okhttp:2.2.0'</code> dependency in example is not necessary as <code>compile 'io.grpc:grpc-okhttp:0.9.0'</code> was modified to be self contained.</p>
  
  <p>When the gRPC service method is called from the main activity it works fine.</p>
  
  <p>I suspect that the <code>grpc-okhttp</code> must be initialized in some way but have no clue how.</p>