Fix `File#write_buffer` to always return the given `io` #132

	name: Tests

	on: [push, pull_request]

	jobs:
	test:
	strategy:
	fail-fast: false
	matrix:
	os: [ubuntu]
	ruby: ['3.0', '3.1', '3.2', '3.3', head, jruby, jruby-head, truffleruby, truffleruby-head]
	include:
	- { os: macos , ruby: '3.0' }
	- { os: windows, ruby: '3.0' }
	# head builds
	- { os: windows, ruby: ucrt }
	- { os: windows, ruby: mswin }
	runs-on: ${{ matrix.os }}-latest
	continue-on-error: ${{ endsWith(matrix.ruby, 'head') \|\| matrix.os == 'windows' }}
	steps:
	- name: Checkout rubyzip code
	uses: actions/checkout@v4

	- name: Install and set up ruby
	uses: ruby/setup-ruby@v1
	with:
	ruby-version: ${{ matrix.ruby }}
	rubygems: '3.2.3'
	bundler-cache: true

	- name: Run the tests
	env:
	RUBYOPT: -v
	JRUBY_OPTS: --debug
	FULL_ZIP64_TEST: 1
	run: bundle exec rake

	- name: Coveralls
	if: matrix.os == 'ubuntu' && !endsWith(matrix.ruby, 'head')
	uses: coverallsapp/github-action@v2
	with:
	github-token: ${{ secrets.github_token }}
	flag-name: ${{ matrix.ruby }}
	parallel: true

	test-yjit:
	strategy:
	fail-fast: false
	matrix:
	os: [ubuntu, macos]
	ruby: ['3.1', '3.2', '3.3', head]
	runs-on: ${{ matrix.os }}-latest
	continue-on-error: true
	steps:
	- name: Checkout rubyzip code
	uses: actions/checkout@v4

	- name: Install and set up ruby
	uses: ruby/setup-ruby@v1
	with:
	ruby-version: ${{ matrix.ruby }}
	bundler-cache: true

	- name: Run the tests
	env:
	RUBYOPT: --enable-yjit -v
	FULL_ZIP64_TEST: 1
	run: bundle exec rake

	finish:
	needs: test
	runs-on: ubuntu-latest
	steps:
	- name: Coveralls Finished
	uses: coverallsapp/github-action@v2
	with:
	github-token: ${{ secrets.github_token }}
	parallel-finished: true

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