I used a man-in-the-middle program to get the http2 source data.
I got a HEADERS frame like this after I split and shunt the data I got.
This frame is the first HEADERS frame returned by the server in this connection.
[enter image description here][1]
Data analysis：
Frame len : 0x00 00 99
Frame type:0x01(HEADERS)
Frame Flag:0x05(END_STREAM(0x1) | END_HEADERS(0x4))
Frame StreamID: 0x00 00 00 01
The unknown three bytes(0x3f 0xe1 0x5f Protocol does not use these three bytes)
(Dropping these three bytes into the HPACK parser causes an error)
0x8b:(:status 304 )
All HEADERS:
[enter image description here][2]
I wonder why there are these fixed three bytes and it doesn't seem to come up every time.
[1]: https://i.stack.imgur.com/hMmIi.png
[2]: https://i.stack.imgur.com/uOI4Z.png
