The parser which is underlying http\Header and http\Message.
This class has been added in v2.3.0.
Most of this states won't be returned to the user, because the parser immediately jumps to the next expected state.
Retrieve the current state of the parser.
Parse a string.
int http\Header\Parser::parse(string $data, int $flags, array &$message = NULL)
Parse a stream.
int http\Header\Parser::stream(resource $stream, int $flags, array &$headers)