future.go
func (u *userSnapshotFuture) Open() (*SnapshotMeta, io.ReadCloser, error) {
	if u.opener == nil {
		return nil, nil, fmt.Errorf("no snapshot available")
	} else {
		// Invalidate the opener so it can't get called multiple times,
		// which isn't generally safe.
		defer func() {
			u.opener = nil
		}()
		return u.opener()
	}
}
func (u *userSnapshotFuture) Open() (*SnapshotMeta, io.ReadCloser, error) {
	if u.opener == nil {
		return nil, nil, fmt.Errorf("no snapshot available")
	} else {
		// Invalidate the opener so it can't get called multiple times,
		// which isn't generally safe.
		defer func() {
			u.opener = nil
		}()
		return u.opener()
	}
}
func ( u * userSnapshotFuture ) Open ( ) ( * SnapshotMeta , io . ReadCloser , error ) { if u . opener == nil { return nil , nil , fmt . Errorf ( " " ) } else { // Invalidate the opener so it can't get called multiple times, // which isn't generally safe. defer func ( ) { u . opener = nil } ( ) return u . opener ( ) } }
// Open is a function you can call to access the underlying snapshot and its
// metadata.
Open is a function you can call to access the underlying snapshot and its metadata .