CompileTime performance measurement

[timepp via Digitalmars-d]

On Sunday, 4 September 2016 at 04:24:34 UTC, rikki cattermole 
wrote:
> void writeln(T...)(T args) {
> 	if (__ctfe){
> 		debug {
> 			__ctfeWriteln(args);
> 		}
> 	} else {
> 		// ... current implementation
> 	}
> }
>
> Are you sureeeee?
any usage example?

consider a normal usage:
writeln("done.");

I just want a runtime output. how can I tell the compiler not to 
print "done." at compile time?