func NewReader(f io.ReaderAt, size int64) (*Reader, error) {
	return NewReaderEncrypted(f, size, nil)
}
func NewReader(f io.ReaderAt, size int64) (*Reader, error) {
	return NewReaderEncrypted(f, size, nil)
}
func NewReader ( f io . ReaderAt , size int64 ) ( * Reader , error ) { return NewReaderEncrypted ( f , size , nil ) }
// NewReader opens a file for reading, using the data in f with the given total size.
NewReader opens a file for reading using the data in f with the given total size .