Rtsp: Support play rtsp stream. #279

Job	Run time
multiple-arch-armv7	3m 36s
cygwin64-cache	4m 47s
multiple-arch-aarch64	3m 54s
utest-regression-blackbox-test	1m 20s
fast	1s
cygwin64	5m 39s
build-ubuntu18	1m 23s
build-ubuntu16	1m 6s
build-cross-aarch64	1m 14s
build-centos7	1m 20s
build-cross-arm	1m 27s
build-ubuntu20	1m 8s
coverage	1m 44s
multiple-arch-amd64	1m 25s
test-done	0s
	30m 4s

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