public ConcurrencyLimitBuilder timeout(Duration timeout) {
        requireNonNull(timeout, "timeout");
        timeoutMillis(timeout.toMillis());
        return this;
    }
Sets the amount of time until this decorator fails the request if the request was not
delegated to the {@code delegate} before then.
core/src/main/java/com/linecorp/armeria/client/limit/ConcurrencyLimitBuilder.java