modifyFile method
Implementation
void modifyFile(String path, String content) {
var data = _pathToData[path];
if (data is! _FileData) {
throw FileSystemException(path, 'Not a file.');
}
_pathToData[path] = _FileData(
bytes: utf8.encode(content) as Uint8List,
timeStamp: nextStamp++,
);
_notifyWatchers(path, ChangeType.MODIFY);
}