improve the type safety of transmitter

[oldratlee]

capture() --captured--> replay() --backup--> restore()
                                   |
                        clear()  --/             

capture/replay/clear/restore method in Transmitter is not type-safe(use generic type Object).

transmittable-thread-local/src/main/java/com/alibaba/ttl/TransmittableThreadLocal.java

Lines 362 to 370 in 2a7667a

	public static class Transmitter {
	/**
	* Capture all {@link TransmittableThreadLocal} and registered {@link ThreadLocal} values in the current thread.
	*
	* @return the captured {@link TransmittableThreadLocal} values
	* @since 2.3.0
	*/
	@NonNull
	public static Object capture() {

improve the type safety of transmitter

• the input of replay should be constricted to the output of capture.
• the input of restore should be constricted to the output of replay/clear.

[oldratlee]

implemented in v3(developing)