── 被查的那笔单（读自上一发的原始应答，非手抄）──
  trade_no     = 200001070X4326092816045010002
  pay_trace_no = probe20260928160450h5
  result_code  = PAY_SUCCESS  （下单受理，尚未被扫/未支付）

── 将发送（不含密钥；sign 打码）──
{
  "inst_no": "900112",
  "mch_no": "Y52211090004",
  "query_trace_no": "483a97c660a14921942751ba3ad4af79",
  "trade_no": "200001070X4326092816045010002",
  "sign": "<len=32>"
}

── 出站 ──
  POST https://test.gdyfsk.com/yfpay/v3/queryorder
  bytes = 190

── 上游应答 ──
  http_code = 200, bytes = 614
  attach           = null
  coupon_amount    = null
  discount_amount  = '0'
  end_time         = null
  mch_name         = '建行小店基本休息修改'
  mch_no           = 'Y52211090004'
  pay_amount       = '1'
  pay_time         = '20260928160450'
  pay_trace_no     = 'probe20260928160450h5'
  pay_type         = '300'
  qd_trade_no      = null
  query_trace_no   = '483a97c660a14921942751ba3ad4af79'
  receipt_amount   = '0'
  result_code      = 'PAY_IN_PROCESS'
  return_code      = 'SUCCESS'
  return_msg       = '用户支付中'
  shop_name        = ''
  shop_no          = ''
  sign             = '18146ea94b94f4264992243d90d199be'
  td_trade_no      = null
  total_amount     = '1'
  trade_no         = '200001070X4326092816045010002'
  trade_state      = 'USERPAYING'
  user_id          = null

── 入站验签（null 不参与）──
  参与签名字段数 = 17
  重算 == 上游 sign : True