Implement cross-thread MediaSource attachments (#4314) #1670

Job	Run time
android-arm / initialize	43s
android-arm64 / initialize	45s
android-x86 / initialize	42s
android-x86 / docker-build-image	3m 8s
android-x86 / docker-unittest-image	0s
android-arm / docker-build-image	3m 12s
android-arm / docker-unittest-image	0s
android-arm64 / docker-build-image	3m 2s
android-arm64 / docker-unittest-image	0s
android-arm64 / arm64_devel	22m 5s
android-arm64 / arm64_debug	18m 26s
android-x86 / x86_devel	18m 20s
android-arm64 / arm64_qa	11m 13s
android-x86 / x86_debug	19m 2s
android-arm64 / arm64_gold	10m 59s
android-x86 / x86_qa	11m 25s
android-x86 / x86_gold	11m 50s
android-arm / arm_devel	20m 52s
android-arm / arm_debug	18m 25s
android-arm / arm_qa	11m 0s
android-arm / arm_gold	11m 40s
android-x86 / ${{ matrix.name }}_on_device_${{ matrix.shard }}	0s
android-x86 / ${{ matrix.name }}_${{ matrix.shard }}_test	0s
android-arm / arm_on_device_0	21m 41s
android-arm / arm_on_device_1	10m 5s
android-arm / ${{ matrix.name }}_${{ matrix.shard }}_test	0s
android-arm / arm_on_device_2	1h 27m 10s
android-arm / arm_on_device_3	24m 9s
android-arm / arm_on_device_black_box_test	14m 2s
android-arm64 / arm64_on_device_0	15m 42s
android-arm64 / arm64_on_device_1	10m 39s
android-arm64 / ${{ matrix.name }}_${{ matrix.shard }}_test	0s
android-arm64 / arm64_on_device_2	29m 53s
android-arm64 / arm64_on_device_3	15m 39s
android-arm64 / arm64_on_device_black_box_test	4m 44s
upload-release-artifacts	0s
	7h 10m 33s

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