protected final boolean isRequestStartTimeSet() {
        return requestStartTimeSet;
    }
Returns whether the request start time has been specified. If not specified, the builder will use
the current time returned by {@link #requestStartTimeNanos()} and {@link #requestStartTimeMicros()}
as the request start time.
core/src/main/java/com/linecorp/armeria/common/AbstractRequestContextBuilder.java