code: function _read(size) {
    /* jshint validthis: true */
    if (this.finished) {
      this.push(null);
    } else {
      if (!this.reading) {
        this.reading = true;
        var context = {
          stream: this
        };
        this.call.recvMessageWithContext(context);
      }
    }
  }
docs: Read the next object from the stream.
  @private
  @param {*} size Ignored because we use objectMode=true