code: function handleClientStreaming(call, handler, metadata) {
    var stream = new ServerReadableStream(call, metadata, handler.deserialize);
    stream.on('error', function(error) {
      handleError(call, error);
    });
    stream.waitForCancel();
    handler.func(stream, function(err, value, trailer, flags) {
      stream.terminate();
      if (err) {
        if (trailer) {
          err.metadata = trailer;
        }
        handleError(call, err);
      } else {
        sendUnaryResponse(call, value, handler.serialize, trailer, flags);
      }
    });
  }
docs: User provided method to handle client streaming methods on the server.
  @callback grpc.Server~handleClientStreamingCall
  @param {grpc~ServerReadableStream} call The call object
  @param {grpc.Server~sendUnaryData} callback The callback to call to respond
  to the request
   
  Fully handle a client streaming call
  @access private
  @param {grpc.internal~Call} call The call to handle
  @param {Object} handler Request handler object for the method that was called
  @param {grpc~Server.handleClientStreamingCall} handler.func The handler
  function
  @param {grpc~deserialize} handler.deserialize The deserialization function
  for request data
  @param {grpc~serialize} handler.serialize The serialization function for
  response data
  @param {grpc.Metadata} metadata Metadata from the client