def reserve_stream(**args)
      next_id = @max_stream_ids[0] + 2
      stream = stream(next_id)
      stream.set_state(:reserved_local)
      stream.update_dependency(**args)
      stream
    end
def reserve_stream(**args)
      next_id = @max_stream_ids[0] + 2
      stream = stream(next_id)
      stream.set_state(:reserved_local)
      stream.update_dependency(**args)
      stream
    end
Reserves a new stream to server push.
 @param args [Hash] The argument to pass to Stram.new.