openRead abstract method

Creates a new independent Stream for the contents of this file.

If start is present, the file will be read from byte-offset start. Otherwise from the beginning (index 0).

If end is present, only bytes up to byte-index end will be read. Otherwise, until end of file.

In order to make sure that system resources are freed, the stream must be read to completion or the subscription on the stream must be cancelled.

If File is a named pipe then the returned Stream will wait until the write side of the pipe is closed before signaling "done". If there are no writers attached to the pipe when it is opened, then Stream.listen will wait until a writer opens the pipe.

An error opening or reading the file will appear as a FileSystemException error event on the returned Stream, after which the Stream is closed. For example:

// This example will print the "Error reading file" message and the
// `await for` loop will complete normally, without seeing any data
// events.
final stream = File('does-not-exist')
    .openRead()
    .handleError((e) => print('Error reading file: $e'));
await for (final data in stream) {
  print(data);
}