/** Get matching method. */
 private MethodDescriptor getMethod(
     SocketRpcProtos.Request rpcRequest, ServiceDescriptor descriptor) throws RpcException {
   MethodDescriptor method = descriptor.findMethodByName(rpcRequest.getMethodName());
   if (method == null) {
     throw new RpcException(
         ErrorReason.METHOD_NOT_FOUND,
         String.format(
             "Could not find method %s in service %s",
             rpcRequest.getMethodName(), descriptor.getFullName()),
         null);
   }
   return method;
 }