class Mail::Message

def set_envelope_header

def set_envelope_header
  raw_string = raw_source.to_s
  if match_data = raw_string.match(/\AFrom\s+([^:\s]#{Constants::TEXT}*)#{Constants::LAX_CRLF}/m)
    set_envelope(match_data[1])
    self.raw_source = raw_string.sub(match_data[0], "")
  end
end