improve: rework `VoiceModel` #2841

Job	Run time
actionlint	17s
build-and-test-java-api (windows-latest)	5m 38s
build-and-test-java-api (macos-latest)	2m 46s
build-and-test-java-api (ubuntu-latest)	2m 53s
build-and-test-python-api (windows-latest)	5m 17s
build-unix-cpp-example (macos-latest, osx-x64-cpu-cpp-shared)	1m 29s
build-and-test-python-api (macos-latest)	3m 5s
build-unix-cpp-example (ubuntu-latest, linux-x64-cpu-cpp-shared)	1m 43s
build-and-test-python-api (ubuntu-latest)	3m 9s
build-windows-cpp-example	5m 18s
c-header	46s
rust-lint	3m 38s
rust-integration-test-strategy-matrix	1s
rust-unit-test	5m 23s
shellcheck	13s
validate-cargo-lock	21s
rust-integration-test (macos-12)	2m 32s
rust-integration-test (ubuntu-20.04)	1m 41s
	46m 10s

Provide feedback