FIT Stellar: Content errors

Quite a few tests are failing with the same issue concerning content:

Expected :["world","mars","hello"]
Actual   :[["world","mars"],[]]

Expected :{"created":true,"age":12,"foo":"bar"}
Actual   :{"created":[],"age":[],"foo":[]}

Root Issue:

The Serializer used is causing this (ReflectionSystemTextJsonSerializer). When no transcoder is passed to operations, the cluster's default TypeSerializer is used. I suspect the underlying System.Text.JsonSerializer to be at the root if this, since it works quite differently to the Newtonsoft version, however it ultimately likely is caused by how we use it.

Changing the Cluster's default TypeSerializer to DefaultSerializer.Instance (which uses Newtonsoft's JsonSerializer) fixes these issue.