Simple log collector using libuv ( don't work )

#include <string>
#include <cstdio>
#include <unordered_map>
#include <boost/coroutine2/all.hpp>
#include "uvw.hpp"

using namespace std::literals;

const auto path = "/Users/Carter/test"s;

template<typename EventType, typename EmitterType>
EventType awaitEvent(std::shared_ptr<uvw::Loop>& loop, std::shared_ptr<EmitterType>& emitter) {
    using coro_t = boost::coroutines2::coroutine<EventType>;

    typename coro_t::pull_type source([&](typename coro_t::push_type& sink) {
        typename EmitterType::template Connection<EventType> ok;
        auto err = emitter->template once<uvw::ErrorEvent>([&](uvw::ErrorEvent &error, auto&) {
            emitter->template erase(ok);
            throw error;
        });
        ok = emitter->template once<EventType>([&](EventType& event, auto&) {
            emitter->template erase(err);
            sink(std::move(event));
        });
        loop->run<uvw::Loop::Mode::ONCE>();
    });
    auto result = std::move(source().get());
    source();
    return result;
}

int main() {
    using namespace uvw;

    auto loop = Loop::getDefault();
    auto fsEventHandle = loop->resource<FsEventHandle>();
    std::unordered_map<std::string, size_t> progresses;

    fsEventHandle->on<FsEventEvent>([&](FsEventEvent& event, FsEventHandle& handle) {
        const char *str;
        switch (event.flags) {
            case (int)FsEventHandle::Watch::RENAME:
                str = "RENAME";
                break;

            case (int)FsEventHandle::Watch::CHANGE:
                str = "CHANGE";
                break;

            case (int)FsEventHandle::Watch::RENAME | (int)FsEventHandle::Watch::CHANGE:
                str = "RENAME | CHANGE";
                break;

            default:
                str = "";
                break;
        }
        std::printf("[Detect changes] %s: %s\n", event.filename, str);

        auto fileReq = loop->resource<FileReq>();

        fileReq->open(path + "/" + event.filename, Flags<FileReq::FileOpen>(FileReq::FileOpen::RDONLY), S_IRUSR);

        awaitEvent<FsEvent<FsReq::Type::OPEN>>(loop, fileReq);

        fileReq->stat();
        const auto fileSize = awaitEvent<FsEvent<FsReq::Type::STAT>>(loop, fileReq).stat.st_size;

        const auto progress = progresses.emplace(event.filename, 0).first->second;

        fileReq->read(progress, static_cast<unsigned int>(fileSize - progress));
        const auto readEvent = awaitEvent<FsEvent<FsReq::Type::READ>>(loop, fileReq);
        const auto fileContent = std::string(readEvent.data.get(), readEvent.size);
        std::printf("[Content appended] %s: %s", event.filename, fileContent.c_str());

        fileReq->close();
        awaitEvent<FsEvent<FsReq::Type::CLOSE>>(loop, fileReq);
    });

    fsEventHandle->start(path);
    loop->run();
}