libhttp-parser2.1 2.1-2 (s390x binary) in ubuntu zesty

 It parses both requests and responses. The parser is designed to be used in
 performance HTTP applications. It does not make any syscalls nor allocations,
 it does not buffer data, it can be interrupted at anytime. Depending on your
 architecture, it only requires about 40 bytes of data per message stream (in
 a web server that is per connection).