Draw looping status -- best way of checking?

What is the best way of checking on the current Processing loop()/noLoop() status?

I have encountered situations in which I want to toggle looping rather than set it -- a simple example is: press space to pause/un-pause. I couldn't find anything in the language reference on looping status -- e.g. nothing referenced from loop() or noLoop().

• isLooping(): in the Processing javadocs I found the PApplet.isLooping() method -- however, I'm not sure if this is undocumented / do-not-use.
• if(looping): in a bug report I found mention of a "looping" flag. Checking it works -- I can even set it directly, and it appears to have the same effect as loop() / noLoop() -- but I couldn't locate it in the github source, and it seems very undocumented...?

I went ahead and created a sketch that demonstrates four methods of toggling the draw loop by pressing 1 / 2 / 3 / 4. All four methods work.

boolean myLooping = true;

int bgBlue = 0;
void draw(){
    background( 0, 0, bgBlue );
    bgBlue = (bgBlue+3)%255;
}

void keyPressed(){
    switch(key){
        case '1':
            if(myLooping){ noLoop(); }
            else { loop(); }
            myLooping = !myLooping;
            break;
        //// check the `isLooping()` method
        case '2':
            if(isLooping()){ noLoop(); }
            else { loop(); }
            break;
        //// check `looping` and set with loop()/noLoop()
        case '3':
            if(looping){ noLoop(); }
            else { loop(); }      
            break;
        //// flip `looping` directly
        case '4':
            looping = !looping;
            break;
    }
}

Just writing looping = !looping; is the most concise, but it is also the most undocumented. Given how complex the looping model is in Processing, any advice on advantages / drawbacks to using any of these methods (or others not mentioned here) to detect the looping status or to toggle it?