public static boolean isStreamCancelling(Throwable cause) {
        // TODO(minwoox): return true if the cause is "io.grpc.StatusRuntimeException: CANCELLED"
        requireNonNull(cause, "cause");
        if (cause instanceof UnprocessedRequestException) {
            cause = cause.getCause();
            assert cause != null;
        }

        for (ExceptionClassifier classifier : exceptionClassifiers) {
            try {
                if (classifier.isStreamCancelling(cause)) {
                    return true;
                }
            } catch (Throwable t) {
                // ignore it.
            }
        }
        return false;
    }
Returns {@code true} if the specified exception will cancel the current request or response stream.
core/src/main/java/com/linecorp/armeria/common/util/Exceptions.java