1________________________________
  open FH, ">&2" ;
    show(*FH)        => GLOB               fileno=4  test=OK     can NOT 'autoflush'
    show(\*FH)       => ref:GLOB           fileno=4  test=OK     can NOT 'autoflush'
    show(*FH{IO})    => ref:FileHandle     fileno=4  test=undef  can 'autoflush'

  2________________________________
  open my $OUT, ">&2" ;
    show($OUT)       => ref:GLOB           fileno=5  test=OK     can NOT 'autoflush'
    show(*$OUT{IO})  => ref:FileHandle     fileno=5  test=undef  can 'autoflush'

  3________________________________
  my $ih = new IO::Handle ;
  reftype($ih) = GLOB
  open $ih, ">&2" ;
    show($ih)        => ref:IO::Handle     fileno=6  test=OK     can 'autoflush'
    show(*$ih{IO})   => ref:FileHandle     fileno=6  test=undef  can 'autoflush'

  4________________________________
  my $fh = new FileHandle ;
  reftype($fh) = GLOB
  open $fh, ">&2" ;
    show($fh)        => ref:FileHandle     fileno=7  test=OK     can 'autoflush'
    show(*$fh{IO})   => ref:FileHandle     fileno=7  test=undef  can 'autoflush'