* Get concrete types out of dynamic payload
wip
pull out value setting to func
* Add TestEventSTream_SetPayloadValue
Add more assertions
use alias type in unmarshalJSON to handle payload rawmessage
shorten unmarshal and remove anonymous wrap struct
* use map structure and helper functions to return concrete types
* ensure times are properly handled
* update test name
* put all decode logic in a single function
Co-authored-by: Kris Hicks <khicks@hashicorp.com>
