Add support for DisallowUnknownFields from json package. #18
Description
https://pkg.go.dev/encoding/json#Decoder.DisallowUnknownFields
Add support to this, may be by a flag to gencodec?
{{ message }}
https://pkg.go.dev/encoding/json#Decoder.DisallowUnknownFields
Add support to this, may be by a flag to gencodec?