注释类型 RunListener.ThreadSafe

@Documented
@Target(TYPE)
@Retention(RUNTIME)
public static @interface RunListener.ThreadSafe

Indicates a RunListener that can have its methods called concurrently. This implies that the class is thread-safe (i.e. no set of listener calls can put the listener into an invalid state, even if those listener calls are being made by multiple threads without synchronization).