### Question:
ForwardingClientStreamListener implements ClientStreamListener { @Override public void headersRead(Metadata headers) { delegate().headersRead(headers); }  @Override void headersRead(Metadata headers); @Override void closed(Status status, Metadata trailers); @Override void closed(Status status, RpcProgress rpcProgress, Metadata trailers); @Override void messagesAvailable(MessageProducer producer); @Override void onReady(); @Override String toString();  }### Answer:
@Test public void headersReadTest() { Metadata headers = new Metadata(); forward.headersRead(headers); verify(mock).headersRead(same(headers)); }