This UnmarshalJSON was never called. The decode function is passed a map[string]interface
so it has no way of knowing that this function exists.
Tested by adding a panic to this function and watching the tests pass.
I attempted to use this Unmarshal function by passing in the type, however the tests
showed that it does not work. The test was failing to parse the request.
If the performance of this endpoint is indeed critical we can solve the problem by adding
all the fields to the request struct and handling the normalziation without a custom Unmarshal.
