func (w *objectWriter) Checkpoint() (ID, error) {
	w.mu.Lock()
	defer w.mu.Unlock()

	return w.checkpointLocked()
}
// Checkpoint returns object ID which represents portion of the object that has already been written.
// The result may be an empty object ID if nothing has been flushed yet.
Checkpoint returns object ID which represents portion of the object that has already been written.
The result may be an empty object ID if nothing has been flushed yet.
// Checkpoint returns object ID which represents portion of the object that has already been written . // The result may be an empty object ID if nothing has been flushed yet .
func (w *objectWriter) Checkpoint() (ID, error) {
	w.mu.Lock()
	defer w.mu.Unlock()
	return w.checkpointLocked()
}
func ( w * objectWriter ) Checkpoint ( ) ( ID , error ) { w . mu . Lock ( ) defer w . mu . Unlock ( ) return w . checkpointLocked ( ) }
Checkpoint returns object ID which represents portion of the object that has already been written.
Checkpoint returns object ID which represents portion of the object that has already been written .