Should be called only when status code is in error state. Normally with 4xx or 5xx.

try to extract `bytes` bytes from the front return # of bytes actually extracted

try to extract `bytes` bytes from front elemnt (iov[0]) return the pointer if succeeded, or nullptr otherwise (alloc failed, or not enough data, etc.)

As some parsers don't support text length, they only support null terminated strings, so we have to convert the last trailer to '\0', while making the

convert oss last modified time, e.g. "Fri, 04 Mar 2022 02:46:25 GMT"

result of the operation

result of the operation