Constant MAX_BODY 

pub const MAX_BODY: usize = _; // 134_217_728usize

#1771 review: the largest body pump accepts. A Content-Length is otherwise trusted and allocated in full before the body arrives, so one corrupted digit could abort the process. A frame over this is unrecoverable framing, like a missing Content-Length. 128 MiB is far above any real message (a didOpen carries one file’s text).