Some services need to send data in chunks to the clients and also allow a way of canceling the action before it is completed. For these cases register the action as a stream():

bridge.service('my-service')
  .plugin(streamsService)
  .stream('myStreamingMethod', function(stream, param) {
    if (param === 'foo') {
      stream.write('bar');
    }

    if (param === 'dolor') {
      // abort() is the way to signal to client that action failed
      stream.abort(new TypeError('invalid argument "dolor"'));
      return;
    }

    var timeout = setTimeout(function() {
      stream.write('baz');
      // close() signals that action finished with success
      stream.close();
    }, 10);

    // you should implement the `cancel` method on the `stream` if your service
    // supports cancellation
    stream.cancel = function(reason) {
      clearTimeout(timeout);
      // you can return a promise if cancel is async; or omit return if action
      // is synchronous or you don't want to notify the client about completion
    };
  });

var client = bridge.client('my-service')
  .plugin(streamsClient);

var stream = client.stream('myStreamingMethod', 'foo');

// called every time the service sends some data
stream.listen(function(data) {
  console.log('data:', data);
});

// "closed" is a Promise that will be fullfilled when stream is closed with
// success or rejected when the service "abort" the operation
stream.closed.then(onStreamClose, onStreamAbort);

// important to note that not all services are able to handle cancellation
// in those cases the promise will be rejected
stream.cancel('because I want').then(onCancelSuccess, onCancelError);

PS: The streaming implementation is very basic and doesn't handle backpressure, buffering and piping; it is just a simple event bridge between the service and the client. This was done on purpose to avoid complexity.

The methods close(), abort() and write() return Promises that can be used to validate if action was executed (eg. write have no effect after close so promise will be rejected).