fix: short-circuit sending zero attachments (#177) #4

	name: Build
	on:
	push:
	branches:
	- main
	tags:
	- v0.*
	pull_request:

	env:
	CARGO_INCREMENTAL: 0

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

	jobs:
	build_and_test:
	name: cargo build
	runs-on: ubuntu-latest
	env:
	RUSTFLAGS: -D warnings
	steps:
	- name: Checkout repository
	uses: actions/checkout@v2

	- name: Setup Rust toolchain
	uses: actions-rs/toolchain@v1
	with:
	toolchain: stable

	- name: Configure CI cache
	uses: Swatinem/rust-cache@v2

	- name: Build
	uses: actions-rs/cargo@v1
	with:
	command: build
	args: --all-targets

	- name: Run tests
	uses: actions-rs/cargo@v1
	with:
	command: test
	args: --all-targets

	rustfmt:
	name: rustfmt
	runs-on: ubuntu-latest
	steps:
	- name: Checkout repository
	uses: actions/checkout@v2

	- name: Setup Rust toolchain
	uses: actions-rs/toolchain@v1
	with:
	profile: minimal
	toolchain: stable
	components: rustfmt

	- name: Check code format
	uses: actions-rs/cargo@v1
	with:
	command: fmt
	args: -- --check

	clippy:
	name: clippy
	runs-on: ubuntu-latest
	steps:
	- name: Checkout repository
	uses: actions/checkout@v2

	- name: Setup Rust toolchain
	uses: actions-rs/toolchain@v1
	with:
	profile: minimal
	toolchain: stable
	components: clippy

	- name: Setup CI cache
	uses: Swatinem/rust-cache@v2

	- name: Run clippy lints
	uses: actions-rs/cargo@v1
	with:
	command: clippy

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