docs: protected synchronized SendRequest makeUnsignedChannelContract(Coin valueToMe) {
          Transaction tx = new Transaction(wallet.getParams());
          if (!getTotalValue().subtract(valueToMe).equals(Coin.ZERO)) {
              tx.addOutput(getTotalValue().subtract(valueToMe), LegacyAddress.fromKey(wallet.getParams(), getClientKey()));
          }
          tx.addInput(contract.getOutput(0));
          return SendRequest.forTx(tx);
      }