Does the 'fair and just reason' standard for withdrawal of a guilty plea properly encompass the post-plea, pre-sentence acquisition of information about a confidential informant?

QUESTION PRESENTED GIVEN GOVERNMENT DISCOVERY DISCLOSURE PRACTICES RELATING TO ITS USE OF CONFIDENTIAL INFORMANTS, DOES THE "FAIR AND JUST REASON" STANDARD FOR WITHDRAWAL OF A GUILTY PLEA PROPERLY ENCOMPASS THE POST-PLEA, PRESENTENCE ACQUISITION OF INFORMATION ABOUT A CONFIDENTIAL INFORMANT THAT WOULD CAUSE A REASONABLE DEFENDANT TO HAVE NOT CHOSEN TO PLEAD GUILTY?