And this isn't even quirky/buggy, it's just the string representation of an error. That said, Go took a while to improve its core error mechanisms and add utilities for matching errors by type instead of its string representation.

In this case, it really is - because until Go 1.19, that function simply returned `errors.New("http: request body too large")`. So until Go 1.19, there really was no other way to check if this error occurred than `err.String() == "http: request body too large"`. Even if we had had errors.Is/As earlier, it wouldn't have helped in this case.