refactor: Remove slot mutex and simplify per blob state #457

Job	Run time
Android Build Only (armv7-linux-androideabi)	1m 29s
Android Build Only (aarch64-linux-android)	1m 24s
check_semver	1m 27s
Cross Build Only (x86_64-unknown-freebsd)	49s
Cross Test (i686-unknown-linux-gnu)	1m 39s
Checking fmt	26s
clippy_check	1m 14s
Checking docs	58s
Minimal Supported Rust Version	1m 6s
codespell	7s
CI Test Suite / Tests (windows-latest, stable, default, x86_64-pc-windows-msvc)	2m 0s
CI Test Suite / Tests (windows-latest, stable, all, x86_64-pc-windows-msvc)	2m 0s
CI Test Suite / Tests (ubuntu-latest, stable, all)	1m 49s
CI Test Suite / Tests (macOS-arm-latest, stable, none)	1m 40s
CI Test Suite / Tests (ubuntu-latest, stable, default)	1m 28s
CI Test Suite / Tests (windows-latest, stable, none, x86_64-pc-windows-msvc)	2m 5s
CI Test Suite / Tests (ubuntu-latest, stable, none)	1m 12s
CI Test Suite / Tests (macOS-arm-latest, stable, default)	1m 34s
CI Test Suite / Tests (macOS-arm-latest, stable, all)	1m 38s
cargo deny	31s
	26m 36s

Provide feedback