Add a hash or checksum function to Power Query (M)

In Power Query (M) in both Power BI and Dataflows there is no checksum or hash function. This means that you have to concatenate and compare columns as a large string which is slow and inefficient. The ability to checksum or hash a record or set of columns in a record would complement incremental refresh perfectly, allowing you to implement change detection and derive edit datetimes for a transformed set of data. A choice of hashing functions would also be a helpful addition. A further benefit would be the ability to generate a single deterministic integer key from a composite join, which supports the Power BI single column join principle, and is much needed with incremental refresh because you can't use an index column where you are only reprocessing part of the dataset.