KeyedMutex

KeyedMutex is used to ensure that only one task can perform a critical section of code at a time, where the critical section of code is associated with an key. KeyedMutex uses a fifo model to prevent starvation. e.g. Async IO operations -

final keyedMutex = KeyedMutex();

Future<void> deleteFileIfExists(File file) async {
  return keyedMutex.withLock(file.absolute, () async {
    if (await file.exists()) {
      await file.delete();
    }
  });
}

The alternative to not using KeyedMutex in the above code would be to use the synchronous version of th IO api's or risk a scenario like below which would otherwise likely cause an exception.

deleteFileIfExists(File("path/to/file"));
deleteFileIfExists(File("path/to/file"));