1. A system comprising: at least one processor; and a memory connected to the at least one processor; the at least one processor configured to: ingest data from at least one data stream, the data comprising a plurality of units of data, each unit of data of the plurality of units of data associated with a first time comprising an associated time and a second time comprising an arrival time, the arrival time comprising a time at which a unit of data of the plurality of units of data arrives at a computing device; evaluate a unit of data from the at least one data stream with respect to compliance with at least a first policy and a second policy of a plurality of policies, wherein the plurality of policies includes an early arrival policy that indicates a maximum early arrival time by which data from the at least one data stream can arrive and be compliant with the early arrival policy, a late arrival policy that indicates a maximum late arrival time by which data from the at least one data stream can arrive and be compliant with the late arrival policy, and an out-of-order policy that indicates a maximum amount of time by which events in a sub-stream or group of the at least one data stream can arrive out-of-order and be compliant with the out-of-order policy, wherein the plurality of policies determine a starting point for reading the at least one data stream to produce output; in response to determining that the unit of data is non-compliant with the first policy and/or the second policy, apply a non-compliance action for the unit of data; and in response to determining that the unit of data is compliant with the first policy and the second policy, produce output from the at least one data stream starting at an output time that complies with the first policy and the second policy.