# UNTESTED
#
# This is for line-by-line reading, not block-by-block reading.
# Adjust as necessary.
sub create_iterator {
    my $original_fh  = \*STDIN;
    my @cached_data  = $original_fh->getline;                # enough to id the file
    my $data_type_id = identify_data_type( \@cached_data );  # Remove from @cached if provided

    my $iterator = iter( sub {
        my $retval;
        if ( $data_type_id ) {
            $retval = $data_type_id;
            $data_type_id = undef;
        }
        elsif ( @cached_data ) {
            $retval = shift( @cached_data );
        }
        else {
            $retval = $original_fh->getline;
        }
        return $retval;
    } );

    return $iterator;
}