withdrawal.go 的 WithdrawalData结构要加tags，要不然还是会出解析异常
type WithdrawalData struct {
Chain crypto.Hash json:"chain"
AssetKey string json:"asset_key"
Address string json:"address"
Tag string
}

另外：
asset –> asset_key
“withdrawal”: {
“chain”: “8dd50817c082cdcdd6f167514928767a4b52426997bd6d4930eca101c5ff8a27”,
“asset”: “0xa974c709cfb4566686553a20790685a47aceaa33”,
“address”: “0x62E2110D4F76e15Ae40FE1e139f249a1F1afd8b5”
},