my %needed_transaction;
while (my %record = get_record()) {
  if ($record{CALL_INIT}
    and $record{CHAN_TYPE} =~ /TCH/
  ) {
    $needed_transaction{ $record{TRAN_ID} } = 1;
  }
  elsif ($record{CALL_RESPONSE}
    and $needed_transaction{ $record{TRAN_ID} }
  ) {
    output_record(%record);
    delete $needed_transaction{ $record{TRAN_ID} };
  }
}