Ensures a stream has a watermark defined, which is required for some operations over streams.
stream_watermark(x, column = "timestamp", threshold = "10 minutes")
An object coercable to a Spark Streaming DataFrame.
The name of the column that contains the event time of the row, if the column is missing, a column with the current time will be added.
The minimum delay to wait to data to arrive late, defaults to ten minutes.