getMasterString

import flash.sampler.*;

function secretlyKeepsLongStringAndReturnsL():String {
    var s:String="Long";
    for(var i:uint;i<20;++i) { s+=s; }
    return s.substr(0,100);
}

var L:String=secretlyKeepsLongStringAndReturnsL();
var m:String=getMasterString(L);

trace(L.length,getSize(L));
trace(m.length,getSize(m));