Syncstream

:mega: New

1. Add some missing methods for completing the standard IO protocol: `closed`, `close()`, `fileno()`, `isatty()`, `readable()`, `writable()`, `seekable()`, `seek()`.
2. Add logics for mainatining the status when buffers are closed.
3. Enable `file.LineFileBuffer()` to capture warning/exception objects. But the captured objects will be stored as text items.
4. Expose the `maxlen` property and the `__len__` property for the buffers.

:wrench: Fix

1. Fix: A server bug causes the warning/exception objects are captured but not recorded by `host.LineHostBuffer()`. This problem has been fixed.
2. Fix: Fix an issue that the getting `__file__` attribute of a placeholder module will cause error.

:floppy_disk: Change

1. Make the `send_eof()`/`send_error()` methods automatically called by the context. Now the mirror/buffer objects will be closed once the context is closed.

:mega: New

1. Provide `.dockerignore` file for removing unexpected files in the built docker image.

:wrench: Fix

1. Fix: Remove an unexpected in-release package `version` which should only appear during the package building.
2. Find a way to include `tests.version` in `sdist` but exclude all `tests` codes in `wheel`.

:floppy_disk: Change

1. Improve the quality of codes.
2. Make the `flake8` warning validator omit the issues exempted by `black`.

:wrench: Fix

1. Fix: Fix an incompatibility issue when `urllib3` is used in `Python==3.6`.

:floppy_disk: Change

1. Improve the workflow versions.

:mega: New

1. Provide the user-friendly APIs `host.LineHostReader()`. This class reproduces all methods of `host.LineHostBuffer()` because the latter one will not be used once it is equipped as the services.
2. Add a `force_stop()` method for `mproc.LineProcBuffer`. This method should be used when the subprocesses will be terminated by `SIG_TERMIATE` or `SIG_KILL`.
3. Add tests for validating whether `Line*Buffer.read()` functionality is correct or not.

:wrench: Fix

1. Fix: If the `last_line` is not flushed by a new line (`\n`) symbol, the `read()` method may not read `size - 1` lines. This unexpected behavior may cause the buffer not to be fully read. Now it has been fixed.
2. Fix: `utils._LazyAttribute` may not initialize a type correctly in some cases. This issue has been fixed by adding a branch for treating the attribute types.
3. Fix: The `version` folder is missing in the docker scripts. Now the folder has been added.

:floppy_disk: Change

1. Replace the typehints `NoReturn` with `Never`.
2. Drop the testing dependency `requests` so that this package would be lighter.

:mega: New

1. Provide full typehints for all modules.
2. Make the optional packages `file` and `host` lazy-loaded. If their dependencies are missing, these modules will be marked as placeholder and their corresponding members will be replaced by `None`.
3. Provide context features to `LineBuffer` and `Line*Mirror`. Entering such contexts will redirect `stdout` and `stderr` to the correspnding buffer/mirror. Note that `Line*Buffer` does not support this feature.
4. Make the version lazy-loaded when buliding the pacakge.
5. Provide the docker scripts for fast-deployment of the testing environment.

:wrench: Fix

1. Fix: Previously, some typehints, for example, the out type of `LineProcBuffer.read()`, are not corrected. Now, these types got fixed.
2. Fix: Previously, `LineBuffer.write()` may return `None` in some cases. Now, such methods will always return `int`.
3. Fix: `LineBuffer` and `Line*Mirror` may not fit the type of `contextlib.redirect_stdout/stderr`. Now, we provide `syncstream.redirect_stdout/stderr` to solve this issue.
4. Fix: PyTest will raises errors if optional dependencies are absent. Now, this issue has been fixed. If any optional dependencies are missing, the corresponding tests will be skipped.
5. Fix: Move `version` as a pacakge because the module version is not compatible with Linux.

:floppy_disk: Change

1. Change the coding style to the Microsoft standards.
2. Make the whole package blackified.
3. Split the standard requirements, locked requirements, and developer's requirements.
4. Drop the dependency `flask-restful` for the optional `host` module. Since the service provider falls back to `flask`, there will be no error handler.
5. Refactor `conftest.py` and `setup` scripts to the modern style.
6. Refactor the GitHub templates for fixing some typos.
7. Update the GitHub Actions scripts to the newest versions.

1. Fix small typos.
2. Bump the dependencies to the newest versions.