feat: add Sleeper based on `futures-timer` #332

	name: CI

	on:
	push:
	branches:
	- main
	pull_request:
	branches:
	- main

	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event_name }}
	cancel-in-progress: true

	env:
	# Minimum Supported Rust Version for backon
	BACKON_MSRV: "1.70"

	jobs:
	check:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- name: Format
	run: cargo fmt --all -- --check
	- name: Clippy
	run: cargo clippy --workspace --all-features --all-targets -- -D warnings

	msrv-check:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- name: Install
	run: rustup toolchain install ${BACKON_MSRV}
	- name: Check MSRV
	run: cargo +${BACKON_MSRV} build --workspace
	env:
	RUST_LOG: DEBUG
	RUST_BACKTRACE: full

	unit:
	runs-on: ${{ matrix.os }}
	strategy:
	matrix:
	os:
	- ubuntu-latest
	- macos-latest
	- windows-latest
	steps:
	- uses: actions/checkout@v4
	- name: Test
	run: cargo test --all-features --workspace
	env:
	RUST_LOG: DEBUG
	RUST_BACKTRACE: full

	nightly-unit:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- run: rustup toolchain install nightly
	- name: Test
	run: cargo +nightly test --all-features --workspace
	env:
	RUST_LOG: DEBUG
	RUST_BACKTRACE: full
	RUSTDOCFLAGS: "--cfg docsrs"

	wasm-unit:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- uses: actions/setup-node@v4
	with:
	node-version: latest
	- name: Install
	run: curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf \| sh
	- run: wasm-pack test --node --all-features -- --skip blocking
	working-directory: backon
	env:
	RUST_BACKTRACE: full

Provide feedback