sub get_stream {
      my ( $self ) = @_;
      my $command = $self->_get_command;

      local *FH;
      # -| is safer, but not portable.
      if ( open FH, "$command |" ) {
          return TAPx::Parser::Iterator->new(\*FH);
      }
      else {
          $self->error("Could not execute ($command): $!");
          return;
      }
  }