w1: perl -e 'while(1){ open(my $fh, ">>:unix", $ENV{PROCLET_TESTFILE}) or die $!; print $fh "w1 $$\n"; close $fh; sleep 1}'
w2: perl -e 'while(1){ open(my $fh, ">>:unix", $ENV{PROCLET_TESTFILE}) or die $!; print $fh "w2 $$\n"; close $fh; sleep 1}'
w1: perl -e 'while(1){ open(my $fh, ">>:unix", $ENV{PROCLET_TESTFILE}) or die $!; print $fh "w1 $$\n"; close $fh; sleep 1}'
w2: perl -e 'while(1){ open(my $fh, ">>:unix", $ENV{PROCLET_TESTFILE}) or die $!; print $fh "w2 $$\n"; close $fh; sleep 1}'