RFR: 8278268 - (ch) InputStream returned by Channels.newInputStream should have fast path for FileChannel targets [v8]

[Lance Andersen]

On Mon, 13 Dec 2021 17:26:39 GMT, Markus KARG <duke at openjdk.java.net> wrote:

>> This sub-issue defines the work to be done to implement JDK-8265891 solely for the particular case of FileChannel.transferFrom(ReadableByteChannel), including special treatment of SelectableByteChannel.
>
> Markus KARG has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Ignoring the case of intermittend zero reads as proposed by Alan Bateman
>   
>   Signed-off-by: Markus Karg <markus at headcrashing.eu>

We will have to separate out the added changes into its own test as we are failing sporadically on some of the windows boxes due to  the execution time.

There is also further cleanup that can be done to existing test.  Attached is an example diff based on the proposed changes in this PR
[8278268-TransferTo-Cleanup.patch.txt](https://github.com/openjdk/jdk/files/7728608/8278268-TransferTo-Cleanup.patch.txt)

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Changes requested by lancea (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/6711