[dist4]message_header // num_bytes | |
[u4]1 // version | |
[u4]0 // interface ID | |
[u4]0 // name | |
[u4]1 // flags: kMessageExpectsResponse is set in a request | |
// for a method that does not take a response. | |
[u4]0 // padding | |
[u8]1 // request_id | |
[anchr]message_header |