[lldb] [llvm] [lldb] Add type hints to gdbclientutils.py and use abstract base class (PR #162172)

[Daniel Sanders via llvm-commits]

dsandersllvm wrote:

Thanks @walter-erquinigo

> Just edited the description so the user `@abstractmethod` doesn't get spammed as this gets merged into various forks of llvm.

Good point 😅. Sorry `@abstractmethod` if I already spammed you

> This looks ok to me I just need you to:
> Remove the pyproject change as discussed

Done in the latest update

> Confirm that your new annotations are all python 3.8 compatible (to the best of your knowledge, Jonas' bot will complain later if we miss something anyway)

Done, for this file vermin is reporting 3.8 minimum both with and without annotations. The other files with pre-existing 3.9 type hints are showing <=3.8 without the annotations and 3.9 with them

> Update the PR description to reflect that

Done. I also added a bit about how I checked the compatibility and correctness

https://github.com/llvm/llvm-project/pull/162172