chronos/src/main/java/com/redmadrobot/chronos/ChronosListener.java
@Contract(pure = true)
    public final boolean isRunning(@NonNull final String tag) {
        final Integer id = mTaggedRequests.get(tag);
        //noinspection SimplifiableIfStatement
        if (id != null) {
            return isRunning(id);
        } else {
            return false;
        }
    }
@Contract(pure = true)
    public final boolean isRunning(@NonNull final String tag) {
        final Integer id = mTaggedRequests.get(tag);
        //noinspection SimplifiableIfStatement
        if (id != null) {
            return isRunning(id);
        } else {
            return false;
        }
    }
Checks if an operation with given launch tag is running.

@param tag a pre-cache key of the operation launch
@return {@code true} if the operation is running, {@code false} if it is not running, or
there was no operation launch with the tag at all