Buffer is different if ::File or ::PerlIO is used (with test)

mking@hal:~/src$ perl -MStream::Buffered::File -MStream::Buffered::PerlIO -E '

# A sort of script plus test case

sub buf { my $fh = shift->rewind; local $/; <$fh> }
my $file = Stream::Buffered::File->new;
$file->print(qw(a b c));
say "-" . buf($file) . "-";
my $perlio = Stream::Buffered::PerlIO->new;
$perlio->print(qw(a b c));
say "+" . buf($perlio) . "+";
exit ! buf($file) == buf($perlio); # Should be 0

'
-abc-
+a b c+