Git Source Tracker Structures 
struct TrackerStorage {
    mapping(uint256 policyId => uint256 trackerIndex) trackerIndexCounter;
    mapping(uint256 policyId => mapping(uint256 trackerIndex => Trackers)) trackers;
    mapping(uint256 policyId => mapping(uint256 trackerIndex => mapping(bytes key => bytes value))) mappedTrackerValues;
    mapping(uint256 policyId => mapping(uint256 trackerIndex => uint256[])) trackerIdToRuleIds;
}