@SuppressWarnings("deprecation")
  @Override
  public CoprocessorRpcChannel coprocessorService(ServerName serverName) {
    return new SyncCoprocessorRpcChannelOverAsync(new RegionServerCoprocessorRpcChannelImpl(
      admin.<Message> newServerCaller().serverName(serverName)));
  }
The {@link Admin} implementation which is based on an {@link AsyncAdmin}.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/AdminOverAsyncAdmin.java