ERR_HTTP2_TRAILERS_NOT_READY

http2stream.sendTrailers() 方法在 Http2Stream 对象触发 'wantTrailers' 事件之前无法调用。只有在为 Http2Stream 设置了 waitForTrailers 选项时，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.】