Introduce nullable types #44

	name: CI
	on:
	push:
	branches:
	- main
	pull_request:

	jobs:
	unit-test:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	go: [ '1.21', '1.20', '1.19', '1.18']
	steps:
	- uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1

	- uses: actions/setup-go@93397bea11091df50f3d7e59dc26a7711a8bcfbe # v4.1.0
	with:
	go-version: ${{ matrix.go }}

	- name: test
	run: go test -race . -v

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