docs: private static int estimateTransacrionSize(UnsignedTransaction unsigned) {
        // Create fake empty inputs
        TransactionInput[] inputs = new TransactionInput[unsigned._funding.length];
        for (int i = 0; i < inputs.length; i++) {
           inputs[i] = new TransactionInput(unsigned._funding[i].outPoint, ScriptInput.EMPTY);
        }
  
        // Create fake transaction
        Transaction t = new Transaction(1, inputs, unsigned._outputs, 0);
        int txSize = t.toBytes().length;
  
        // Add maximum size for each input
        txSize += 140 * t.inputs.length;
  
        return txSize;
     }