Method writeFileOnce

Tests/Libraries/Await/AwaitTest.cpp:655–665

        co_return Result(true);
    }

    static AwaitTask writeFileOnce(AwaitEventLoop& await, const FileDescriptor& file)
    {
        const char           writeBuffer[] = {'t', 'e', 's', 't'};
        AwaitFileWriteResult writeResult;
        SC_CO_TRY(co_await await.fileWrite(file, {writeBuffer, sizeof(writeBuffer)}, &writeResult));
        if (writeResult.numBytes != sizeof(writeBuffer))
        {
            co_return Result::Error("Await file write byte count mismatch");
        }
        co_return Result(true);
    }