our %WA: shared;
  our $WAlock: shared;
...
  my ($key, $dtg, $bytes) = @_;
  if (!defined $WA{$key}) {
    {
      lock $WAlock;
      $WA{$key} = &share({}); #hook shared anon hash;
    
      {
        lock $WA{$key};
        $WA{$key}{PS}=$dtg;          # PS period Start
        $WA{$key}{PE}=$dtg + $secs;  # PE period End
        $WA{$key}{PT}=0;             # PT period Total
        $WA{$key}{stgs} =();         # list of decaying values
        for my $i (0..$rnds-1){
          $WA{$key}{stags}[$i]=0;    # init all stages to 0
        }
      }
    }
  } # end of (! defined) entry being initialized

##</code><code>##

sub reportWA{  # $key
  my $key = shift;

  my $NewWA;

  unshift @{WA{$key}{stags}}, $WA{$key}{PT}; #insert PT at [0]  -line 110
  $NewWA=$WA{$key}{PT};                      # $periodTotal * 1

  $#{@{WA{$key}{stags}}} = $rnds-1;      # truncate off oldest stage
  for my $i (1..$rnds-1){
    ${WA{$key}{stags}}[$i] *=  $wght;  #stag[n] = initial * (wght**n)
    $NewWA += ${WA{$key}{stags}}[$i];
  }
  #plog sprintf "stages =  %s" ,join (", ",@stags);
  $NewWA /= $rnds;
  printf " %d  %d  %8.2f    %s\n" , $key,$WA{$key}{PE} ,$NewWA,
                                 join (", ",@{WA{$key}{stags}});
}


-------
Errors generated start with these :
Scalar value @{WA{$key} better written as ${WA{$key} at ThWgtAvg1.pl line 110.
Useless use of unshift with no values at ThWgtAvg1.pl line 110.
Scalar value @{WA{$key} better written as ${WA{$key} at ThWgtAvg1.pl line 113.
Scalar value @{WA{$key} better written as ${WA{$key} at ThWgtAvg1.pl line 121.
Type of arg 1 to unshift must be array (not hash slice) at ThWgtAvg1.pl line 110, near "}{stags"
syntax error at ThWgtAvg1.pl line 110, near "}{stags"
...