version 1.0.1

Changes since 1.0.0:
- `setup.py` has been replaced with `pyproject.toml`.
- Previously we used a global lock to avoid pipe inheritance race
  conditions on Windows. As of Python 3.7, `close_fds=True` is
  sufficient for this, and is also the default. The lock has been
  removed.

version 1.0.0

Changes since 0.6.4:
- The majority of the API is stabilized as-is. The main visible change
  is that the `try_wait` methods on `Handle` and `ReaderHandle` have
  been renamed to `poll`, for consistency with `subprocess.Popen.poll`
  in the Python standard library. The `try_wait` methods are retained as
  `@deprecated` aliases. Apart from that renaming, the rest of the
  changes are bugfixes or edge case behaviors.
- Fixed a bug where `Handle.poll` could block indefinitely if a child
  process had exited but a longer-lived grandchild process was keeping
  its IO pipes open and its IO threads running (i.e. `stdin_bytes`,
  `stdout_capture`, or `stderr_capture`). Commit 60f57ae.
- `Handle.kill` and `ReaderHandle.kill` no longer wait on child
  processes to exit. `subprocess.Popen` has an undocumented `__del__`
  finalizer, and it lazily cleans up leaked zombie children whenever new
  child processes are spawned. That's sufficient to prevent unbounded
  leaks, and there are also edge cases where waiting on a killed process
  can still block, so Duct now relies entirely on that finalizer. I'm
  porting similar behavior to the Rust implementation, for its
  coordinated v1.0.0 release.
- Duct no longer kills child processes in any circumstance other than
  when you call `.kill()`. Previously Duct would kill child processes
  when closing a `ReaderHandle` that had not been read to EOF, or in
  some pipe spawning error cases.
- The `ReaderHandle.close` method no longer has any effect. Duct no
  longer defines the method, and `ReaderHandle` inherits the no-op
  `IOBase.close`. `ReaderHandle` is still compatible with the `with`
  keyword, but context exit no longer has any effect. The `with` keyword
  has been removed from docs examples, to avoid giving the impression
  that it can do prompt cleanup without relying on finalizers.

version 0.6.4

Changes since 0.6.3:
- Fix a race condition where the kill() method would raise a
  ChildProcessError if the child exited before kill() was called. This
  was caused by a change in the behavior of Popen.send_signal() in
  Python 3.9. See commit 5dfae70.

version 0.6.3

Changes since 0.6.2:
- Added `Handle.pids` and `ReaderHandle.pids`.

version 0.6.2

Changes since 0.6.1:
- Added `ReaderHandle.try_wait`.

version 0.6.1

Changes since 0.6.0:
- ReaderHandle now supports kill().
- Kill methods no longer wait on IO threads to complete. This avoids
  blocking on unkilled grandchildren.

version 0.6.0

Changes since 0.5.1:
- Removed the `sh` function.
- Removed the `then` method.
- Add `Handle.kill` and use `waititd` to make it thread-safe.
- Add `ReaderHandle` and `Expression.reader()`.
- Avoid using threads in many cases.
- Rename stdin/stdout/stderr to stdin_path/stdout_path/stderr_path.
- Add Sphinx docs and doctest the examples.
- This will be the last major release supporting Python 2.

bump version to 0.5.1

Changes since 0.5.0:
- Added `env_remove`.
- Automatically uppercase env var names on Windows.

bump version to 0.5.0

Changes since 0.4.0:
- rename null_* and capture_* to *_null and *_capture
- split out stdin_file/stdout_file/stderr_file
- handle relative exe paths and dir
- add the start method
- make unchecked preserve the exit code

bump version to 0.4.0

Changes since 0.3.0:
- The magic constants NULL/CAPTURE/STDOUT/STDERR have been replaced with
  dedicated methods: null_*/capture_*/stdout_to_stderr/stderr_to_stdout.
  This saves you the trouble of extra imports, and it avoids weird
  typechecking issues like .stdin(CAPTURE) (if that's supposed to be a
  type error, then would need need two different types for NULL).
- The env_remove and env_clear methods have been dropped, and we've gone
  back to the env/full_env API. (Though this time around they're methods
  instead of flags.) This is easier to use and more flexible, and it
  also prevents weird race conditions.
- The cwd method has been renamed to dir. The cmd and cwd names were too
  awkwardly close to each other.