fix block listener

Helius

2022-06-06 953f7999c90d5bfddba501d64f6f89bd6d95c427

 src/main/java/cc/mrbird/febs/dapp/chain/TrxService.java

@@ -103,4 +103,9 @@
    public static void main(String[] args) {
//        System.out.println(INSTANCE.transfer("TFGbYzGv4Zt2nzFM3uU3uCJZY67WKSveG9", BigDecimal.valueOf(5)));;
    }

    @Override
    public BigInteger blockNumber() {
        return null;
    }
}