sub seek {
    my $self = shift;
    my $seek = shift;
    unless ($self->{_is_seekable}) {
        carp "FH is not seekable" if $DEBUG; 
        return 0;
    }

    $self->{_fh}->seek($seek) if defined $seek;
    $self->_init_bits();
    return $self->{_fh}->tell();
}