Is your feature request related to a problem? Please describe.

Currently there are such options as AllowUnknownMsgFields and ValidateUserDefinedFields. We are working in an environment where dictionary changes faster than we would like it to happen. At the same time we do not want messages to be rejected when some new field appears. So we set AllowUnknownMsgFields=Y and ValidateUserDefinedFields=N to allow messages new fields to come through. However, quickfix does not really say when field has been allowed through because of disabled validation.

Describe the solution you'd like

I would like quickfix to log fields which would fail validation if these two options would be AllowUnknownMsgFields=N and ValidateUserDefinedFields=Y. Something like
User Defined Field X is detected
Unknown message field X is detected