wx.request 无法使用multipart/form-data - WXOPEN Club

当前 Bug 的表现（可附上截图）

wx.request 设置content-type 为multipart/form-data ，请求头如下：

POST /mindoffice/visitor_unreservations/subscribeBill HTTP/1.1

Host: qas.zjzlnet.com

Content-Length: 20

Pragma: no-cache

Cache-Control: no-cache

Origin: http://127.0.0.1:34785

User-Agent: Mozilla/5.0 (iPhone; CPU iPhone OS 9_1 like Mac OS X) AppleWebKit/601.1.46 (KHTML, like Gecko) Version/9.0 Mobile/13B143 Safari/601.1 wechatdevtools/1.02.1809111 MicroMessenger/6.5.7 Language/zh_CN webview/ token/61f11dc1d5bc1cfd264bbe33ae8d2f95

content-type: multipart/form-data

Accept: */*

Referer: https://servicewechat.com/wx04c25e121b8ce5df/devtools/page-frame.html

Accept-Encoding: gzip, deflate

Accept-Language: zh-CN,zh;q=0.8

Connection: keep-alive

{"data":"test data"}

提交的参数没有被 boundary 包裹，后台拒绝了请求，提示 no multipart boundary was found