Found pointer to free object

[patricksandquist]

We've been seeing some occasional restarts in our orchestrator service with added load. Looking at the logs, it seems to be a free object pointer:

0xc01f75bff0 alloc unmarked
fatal error: found pointer to free object

This matches the issue identified in https://github.com/segmentio/webhook-functions-consumer/pull/173 and I can also find the segmentio/encoding library in my stack trace. I updated my service to use the stdlib json library and have not seen this issue since.