`AsyncFile.readinto()` has incorrect return type

[sanmai-NL]

Things to check first

• I have searched the existing issues and didn't find my bug already reported there

• I have checked that my bug is still present in the latest release

AnyIO version

4.6.2.post1

Python version

3.12.6

What happened?

For one, AsyncFile.readinto() was declared to return the generic type parameter rather than int, the number of bytes written like the standard library method. Should this method even be available for text IO?

How can we reproduce the bug?

N.A.

[agronholm]

I fixed the immediate reported issue. If you have ideas on how to further improve the type annotations, let me know.

[sanmai-NL]

@agronholm Thanks! I raised a question in addition. I question whether readinto() etc. may even be provided for text IO objects. From my reading of the standard library docs, these are only available for binary IO objects.

[agronholm]

Yeah so there is no way to remove methods from a class just based on the type variables so the method exists but won't work.