use own json marshaller/unmarshaller

[vtolstov]

Can you add ability to use own json marshaler/unmarshaler?
I'm prefer to use https://github.com/json-iterator/go, but somebody may wants jsonb.

[danielvladco]

Hi @vtolstov ,

The json package is used only for maps encode/decode as a workaround.
#4 in this issue I highly suggest not using maps with this plugin.

[vtolstov]

ok, thanks!