在提供的 demo 中，TaskPromise 结构体起到了什么作用？

在提供的 demo 中，TaskPromise 结构体起到了什么作用？

#include <iostream>
#include <coroutine>

template <bool READY>
struct Awaiter {
bool await_ready() noexcept {
std::cout << "await_ready: " << READY << std::endl;
return READY;
}
void await_resume() noexcept {
std::cout << "await_resume" << std::endl;
}
void await_suspend(std::coroutine_handle<>) noexcept {
std::cout << "await_suspend" << std::endl;
}
};

struct TaskPromise {
struct promise_type {
TaskPromise get_return_object() {
std::cout << "get_return_object" << std::endl;
return TaskPromise{std::coroutine_handle<promise_type>::from_promise(*this)};
}
Awaiter<true> initial_suspend() noexcept {
std::cout << "initial_suspend" << std::endl;
return {};
}
Awaiter<true> final_suspend() noexcept {
std::cout << "final_suspend" << std::endl;
return {};
}
void unhandled_exception() {
std::cout << "unhandled_exception" << std::endl;
}
void return_void() noexcept {
std::cout << "return_void" << std::endl;
}
};

void resume() {
std::cout << "resume" << std::endl;
handle.resume();
}

std::coroutine_handle<promise_type> handle;
};

TaskPromise task_func() {
std::cout << "task first run" << std::endl;
co_await Awaiter<false>{};
std::cout << "task resume" << std::endl;
}

int main() {
auto promise = task_func();
promise.resume();

return 0;
}