Remove `Reader::scrach_buffer` field + resulting breaking API changes. #372

	name: Rust CI
	on:
	push:
	branches: [ master ]
	pull_request:
	branches: [ master ]
	jobs:
	build:
	strategy:
	fail-fast: false
	matrix:
	rust: ["1.57.0", stable, beta, nightly]
	os: [ubuntu-latest, windows-latest, macos-latest]
	features: [""]
	runs-on: ${{ matrix.os }}
	steps:
	- uses: actions/checkout@v2
	- uses: actions-rs/toolchain@v1
	with:
	toolchain: ${{ matrix.rust }}
	override: true
	- if: ${{ matrix.rust == '1.57.0' }}
	run: mv Cargo.lock.msrv Cargo.lock
	- name: build
	run: \|
	cargo build --verbose
	feature_check:
	strategy:
	matrix:
	features: ["", "benchmarks"]
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	- uses: actions-rs/toolchain@v1
	with:
	toolchain: nightly
	override: true
	- name: check
	run: \|
	cargo check --tests --no-default-features --features="$FEATURES"
	env:
	FEATURES: ${{ matrix.features }}
	mips_cross:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	- name: add_cross_target
	run: \|
	rustup target add mips64-unknown-linux-gnuabi64
	cargo build --all-features --target mips64-unknown-linux-gnuabi64
	test_all:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	- run: rustup default stable
	- name: test
	run: >
	cargo test -v --all-targets --all-features
	rustfmt:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	- uses: actions-rs/toolchain@v1
	with:
	toolchain: stable
	override: true
	components: rustfmt
	- name: Run rustfmt check
	uses: actions-rs/cargo@v1
	with:
	command: fmt
	args: -- --check

Provide feedback