Fuzzy testing

[nhooyr]

https://blog.kowalczyk.info/article/n/fuzzing-markdown-parser-written-in-go.html

[nhooyr]

Also https://github.com/google/gofuzz/blob/master/fuzz.go and https://github.com/dvyukov/go-fuzz

[nhooyr]

Not sure if this is necessary.

[nhooyr]

Would definitely be fun and nicer than writing a lot of specific tests.

[nhooyr]

can't really use go-fuzz but can write some code to randomly generate a sequence of frames and ensure the library responds properly.

[nhooyr]

I think the current test suite is very thorough, this wouldn't really be necessary.