FILE_FLAG_OVERLAPPED top-level constant Null safety
The file or device is being opened or created for asynchronous I/O. When subsequent I/O operations are completed on this handle, the event specified in the OVERLAPPED structure will be set to the signaled state. If this flag is specified, the file can be used for simultaneous read and write operations. If this flag is not specified, then I/O operations are serialized, even if the calls to the read and write functions specify an OVERLAPPED structure.
const FILE_FLAG_OVERLAPPED = 0x40000000;