This packet is sent by the server when it needs to notify the client of something.
It contains a list of NoticeField objects, which have the following properties:
fieldType (byte): the type of notice -- see the Vertica documentation for the meaning of this code
fieldValue (string): the value for the notice field
noticeFields (List<NoticeField>): the notice fields
getNoticeString(): returns a string containing all the notice fields in this packet
addNoticeField(byte fieldType, string fieldValue): adds a new NoticeField to this packet