The Priority property of the LogMessage2 object is a Read-Only integer between 1 and 10 (1 being the most important - "highest priority"). Priority is used by an application to define the order in which a message condition should be handled relative to other messages. Unlike severity, which defines the criticality of a message, priority is intended to indicate ordering of corrective action. Priority is always an optional part of a message because only an application can determine if it is needed and what its value should be.
The object placeholder is an object expression that evaluates to a LogMessage2 object.