Triggering JS init() hooks from c++ async_hooks_init_function

async_wrap.cc

void AsyncWrap::EmitAsyncInit(Environment* env,
                              Local<Object> object,
                              Local<String> type,
                              double async_id,
                              double trigger_async_id) {
  CHECK(!object.IsEmpty());
  CHECK(!type.IsEmpty());
  AsyncHooks* async_hooks = env->async_hooks();

  // Nothing to execute, so can continue normally.
  if (async_hooks->fields()[AsyncHooks::kInit] == 0) {
    return;
  }

  HandleScope scope(env->isolate());
  Local<Function> init_fn = env->async_hooks_init_function();

  Local<Value> argv[] = {
    Number::New(env->isolate(), async_id),
    type,
    Number::New(env->isolate(), trigger_async_id),
    object,
  };

  TryCatchScope try_catch(env, TryCatchScope::CatchMode::kFatal);
  USE(init_fn->Call(env->context(), object, arraysize(argv), argv));
}