Patch the 'thread' module provided by 'future' if it's already imported, which is likely because pkg_resources imports it if installed.

Also some more cleanup from removing py3.4 support.

Took some tweaking of connection params --- did something change in OS X? And PyPy's GC has apparently changed the way it deals with sockets, we're better off being fully explicit about lifetime.

Fixes #1354. Fixes #1357

- Remove 3.4
- Update to latest 3.x series
- Update to PyPy 7

Tests are not passing locally yet.

Fix a typo in doc/intro.rst

Remove unused

Remove useless variable

Upgrade libuv to 1.24.0

More tweaks for test__fileobject.py on 3.7

Deterministically close GreenFileDescriptorIO backing FileObjectPosix if the (libuv) event loop watchers produce an error.

Especially on Python 3.7, the C-level garbage collection could kick in and close the underlying fileno at an inopportune time, killing an unrelated file, even though there were no Python-level references alive (apparently).

Cast OSError raised by os.lseek into IOError

This cleans up the skips needed.

Don't introduce a reference cycle with the traceback.

In the test, don't use sys.stdout as a non-seekable stream; putting it into non-blocking mode messes up the console. Instead create a pipe for this purpose.

Simplify test cases by splitting FOPosix and FOThread.

Make ThreadPool.join respect the loop.min_sleep_time value.

Setting the size was already doing so. By not using the hardcoded value, this prevents a UserWarning from the libuv backend.

Also rename the attribute to  and implement it for all loops.
Add this to the ILoop interface, and test that all loop implementations correctly implement it with zope.interface.verify.verifyObject.

Fixes #1321.