Add type hints to hpack

[sethmlarson]

No description provided.

[Kriechi]

Tests are still failing - but otherwise this LGTM!

[sethmlarson]

Disappointed by the amount of # type: ignore required. Going to manually take another look before merging.

[graingert]

PR for stricter #type: ignore[...] https://github.com/sethmlarson/hpack/pull/1/files

seems that you can't do Tuple[AnyStr, AnyStr] perhaps it would be better to make frozen attrs classes?

class HeaderTupleLike(Prototocol[AnyStr]):
    name: AnyStr
    value: AnyStr
    indexed: bool

@attr.frozen
class HeaderTuple(Generic[AnyStr]):
    name: AnyStr
    value: AnyStr
    indexed: Literal[True] = attr.field(default=True, init=False)

@attr.frozen
class NeverIndexedHeaderTuple(Generic[AnyStr]):
    name: AnyStr
    value: AnyStr
    indexed: Literal[False] = attr.field(default=False, init=False)

it's unfortunate that this extension of a builtin is part of the public interface though