//static event executingSwingCode(Runnable code);

static transient Set<IVF1<Runnable>> onExecutingSwingCode;
public static void onExecutingSwingCode(IVF1<Runnable> f) { onExecutingSwingCode = createOrAddToSyncLinkedHashSet(onExecutingSwingCode, f); }
public static void removeExecutingSwingCodeListener(IVF1<Runnable> f) { main remove(onExecutingSwingCode, f); }
public static void executingSwingCode(Runnable code) {  if (onExecutingSwingCode != null) for (var listener : onExecutingSwingCode) pcallF_typed(listener, code); }