POST http://localhost:8000/form-params
[FormParams]
param1: value1
param2:
param3: a=b
param4: a%3db

HTTP/1.0 200

# same version as raw
POST http://localhost:8000/form-params
Content-Type: application/x-www-form-urlencoded
```param1=value1&param2=&param3=a%3db&param4=a%253db```

HTTP/1.0 200