Support custom timeout strategies in StreamMessage.timeout(), with built-in support for a token-bucket timeout-limiting strategy

[sjy982]

Currently, StreamMessage.timeout() only supports fixed timeouts.
I’d like to propose adding support for custom timeout strategies via a StreamTimeoutStrategy interface.

Users would implement their own strategy and pass it to timeout(...), for example:

public interface StreamTimeoutStrategy {
     /**
     * Compares the current time (`currentTimeNanos`) with the last event time (`lastEventTimeNanos`)
     * and evaluates whether a timeout has occurred and when the next check should be scheduled.
     */
    StreamTimeoutDecision evaluateTimeout(long currentTimeNanos, long lastEventTimeNanos);
}

public final class StreamTimeoutDecision {
    private static final long NO_NEXT_TIMEOUT = -1L;
    private final boolean timedOut;
    private final long nextScheduleTimeNanos;
}

Basically, I would like to suggest the following two strategies.

1. Default mode (StreamTimeoutMode + duration)

   StreamMessage.timeout(StreamTimeoutMode.UNTIL_NEXT, Duration.ofSeconds(10)); // Internally: new DefaultTimeoutStrategy(StreamTimeoutMode.UNTIL_NEXT, timeoutNanos);

2. A strategy based on the token bucket rate-limiting algorithm. (token-bucket timeout-limiting strategy) Allows occasional network jitter without terminating the stream, but triggers a timeout when delays occur consecutively.
   This prevents unnecessary stream termination due to transient network hiccups.

   StreamMessage.timeout(new TokenBucketTimeoutStrategy(...));