Currently, in aggregation_currentop.js, an assertion to check that timeOpenMicros is greater than timeBeforeCurrentOp - timeAfterTransactionStarts fails sometimes. This is because timeOpenMicros is a server-side metric with microsecond precision whereas timeBeforeCurrentOp and timeAfterTransactionStarts are ISODates with only millisecond precision. The discrepancy in precision causes rounding issues, so the assertion occasionally fails (ex. 2966 is not greater than 3000). We should round timeOpenMicros to have millisecond precision instead.