my $textref = cat_files_ref( ... );
sub cat_files_ref {
  use File::Slurp;
  my $buffer = "";
  for my $file ( @_ ){
    read_file( $bin_file, buf_ref => \$buffer,
{ binmode => ':raw' } ) ;
  }
  return \$buffer;
}

sub cat_files_ref {
  use Path::Tiny;
  my $buffer = "";
  for my $file ( @_ ){
    $buffer .= path( $file )->realpath->slurp_raw;
  }
  return \$buffer;
}

sub cat_files_ref {
  use IO::All;
  my $content;
  for my $file ( @_ ){
    $content << io($file);
  }
  return \$content;
}