Method writev

fs/localfs.cpp:205–209

            return UISysCall(::write(fd, buf, count));
        }
        virtual ssize_t writev(const struct iovec *iov, int iovcnt) override
        {
            thread_yield();
            return UISysCall(::writev(fd, iov, iovcnt));
        }
        virtual ssize_t pread(void *buf, size_t count, off_t offset) override
        {
            thread_yield();