def promise(*args, &callback)
      parent, headers, flags = *args
      promise = new_stream(parent: parent)
      promise.send(
        type: :push_promise,
        flags: flags,
        stream: parent.id,
        promise_stream: promise.id,
        payload: headers.to_a,
      )

      callback.call(promise)
    end
def promise(*args, &callback)
      parent, headers, flags = *args
      promise = new_stream(parent: parent)
      promise.send(
        type: :push_promise,
        flags: flags,
        stream: parent.id,
        promise_stream: promise.id,
        payload: headers.to_a,
      )

      callback.call(promise)
    end
Handle locally initiated server-push event emitted by the stream.

 @param args [Array]
 @param callback [Proc]