Closes the file.
Flushes any pending writes to the file.
Returns the length of the file in bytes
Returns the sync progress of this file, that is, the total byte size of all the blocks of this file that's already been downloaded.
Reads size bytes from the file starting at offset bytes from the beginning of the file.
size
offset
Truncates the file to the given length.
Writes the data to the file at the given offset.