No, you cannot implement a conforming client or server of any protocol by inspecting the wire. How do you know there aren't other cases that you're supposed to

No, you cannot implement a conforming client or server of any protocol by inspecting the wire. How do you know there aren't other cases that you're supposed to handle that simply didn't happen to occur in the sessions that you sniffed? HTTP is the prime example of why being a text protocol doesn't make it simpler.