OpenApiRequestMktAssetRefundDTO

退款请求参数（含 merchantNo、channelType、outOrderNo、refundAmount）

{
    "requestId": "string",
    "timestamp": "string",
    "nonce": "stringstringstri",
    "sign": "string",
    "reqBody": {
        "merchantNo": "string",
        "channelType": 0,
        "outOrderNo": "string",
        "channelOrderNo": "string",
        "refundAmount": 0,
        "assetNo": "string",
        "reason": "string"
    }
}