ERR_HTTP2_TRAILERS_NOT_READY

在 Http2Stream 对象上触发 'wantTrailers' 事件之后，才能调用 http2stream.sendTrailers() 方法。 只有为 Http2Stream 设置了 waitForTrailers 选项，才会触发 'wantTrailers' 事件。

The http2stream.sendTrailers() method cannot be called until after the 'wantTrailers' event is emitted on an Http2Stream object. The 'wantTrailers' event will only be emitted if the waitForTrailers option is set for the Http2Stream.