Don't forget to use local $_ before while ( $_ = $reader->chunk ) {, or you might clobber something without even realizing it. For example, the following snippet replaces the content of @array with false values because $_ is (in turn) a reference to each element of @array:

foreach (@array) {
   ...
   my $reader = ...;
   ...

   while ($_ = $reader->chunk) {
      ...
   }

   ...
}
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The following dies with the run-time error "Modification of a read-only value attempted":

for ('a', 'b') {
   ...
   my $reader = ...;
   ...

   while ($_ = $reader->chunk) {
      ...
   }

   ...
}
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