Problem Aggregation
Represents a list of aggregated problems. These are sent at the end of the build. All Problems that occurred more than once during the build are aggregated and sent as a ProblemAggregation. They won't be sent in between the build only the first one. The aggregation happens based on the ProblemCategory and Label. Therefore, the ProblemCategory and Label are the same for all aggregated problems and are also present in the this aggregation interface.