RFR: 8357847: (ch) WindowsAsynchronousFileChannelImpl should support FFM Buffers [v3]

[Brian Burkhalter]

On Wed, 4 Jun 2025 22:18:03 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> Acquire the scope of a direct buffer before it is used and release it after the task has finished with it, whether the task execution is immediate or pended.
>
> Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8357912: Add similar changes to SimpleAsynchronousFileChannelImpl

Before the change in https://github.com/openjdk/jdk/pull/25531/commits/9d8ed1933340ca01455ba41603386da7dbd964f2, the test `java/nio/channels/AsynchronousFileChannel/Basic.java` failed on Unix for both confined and shared `Arena`s.

The `((DirectBuffer)dst).address()` calls added here are to check the session and its state, and the returned value is ignored. It might be better if something like `void DirectBuffer::checkSession` were available, identical to `DirectBuffer::address` but without returning the address.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/25531#issuecomment-2941748675