Currently, the calculation of the cardinality, frequency and monotonicity metrics in the analyzeShardKey command is resource-intensive and slow. There is upcoming work for optimizing it (WRITING-36520). However, after the optimization the calculation likely still takes minutes for large collections. While waiting for the analyzeShardKey response, a client may disconnect unintentionally due to a network/connection error. To prevent a retry from starting another round of metrics calculation, we should make analyzeShardKey support joining with an in-progress run with the same settings, and caching and returning metrics calculated by a recent run with the same settings. This will also make the client no longer required to maintain a connection while waiting for the response.