message: use constant variable
diff: @@ -614,6 +614,9 @@ pub mod fee {
  impl Default for LinearFee {
  fn default() -> Self { LinearFee::new(155381.0, 43.946) }
  }
  +
  + const TX_IN_WITNESS_CBOR_SIZE: usize = 140;
  + const CBOR_TXAUX_OVERHEAD: usize = 51;
  impl Algorithm for LinearFee {
  fn compute( &self
  , policy: SelectionPolicy
  @@ -649,7 +652,7 @@ pub mod fee {
  let mut tx = Tx::new_with(txins.clone(), txouts.clone());
  let txbytes = cbor::encode_to_cbor(&tx).unwrap();
  - let estimated_fee = (self.estimate(txbytes.len() + 51 + (140 * selected_inputs.len())))?;
  + let estimated_fee = (self.estimate(txbytes.len() + CBOR_TXAUX_OVERHEAD + (TX_IN_WITNESS_CBOR_SIZE * selected_inputs.len())))?;
  // add the change in the estimated fee
  match output_value - input_value - estimated_fee.to_coin() {
  @@ -660,7 +663,7 @@ pub mod fee {
  };
  let txbytes = cbor::encode_to_cbor(&tx).unwrap();
  - let corrected_fee = self.estimate(txbytes.len() + 51 + (140 * selected_inputs.len()));
  + let corrected_fee = self.estimate(txbytes.len() + CBOR_TXAUX_OVERHEAD + (TX_IN_WITNESS_CBOR_SIZE * selected_inputs.len()));
  fee = corrected_fee?;
  