static Thread startThread(O runnable) {
  ret startThread(defaultThreadName(), runnable);
}

static Thread startThread(S name, O runnable) {
  runnable = wrapAsActivity(runnable);
  ret startThread(newThread(toRunnable(runnable), name));
}

static Thread startThread(Thread t) {
  ifndef LeanMode
  _registerThread(t);
  endifndef
  t.start();
  ret t;
}

Began life as a copy of #1004558