fix: process parallel events and potential deadlock in `on_record` #111

Job	Run time
cargo check	32s
cargo fmt	5s
warnings	39s
cargo test (stable on ubuntu-latest)	1m 15s
cargo check (feature combinations)	22s
build tests (wasm)	1m 2s
cargo test (beta on ubuntu-latest)	1m 10s
cargo check (+MSRV -Zminimal-versions) (1.65.0)	3m 21s
cargo test (nightly on ubuntu-latest)	1m 42s
cargo check (+MSRV -Zminimal-versions) (stable)	26s
cargo test (stable on windows-latest)	3m 1s
cargo test (stable on macos-latest)	2m 6s
all systems go!	0s
	15m 41s

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