Use the Throttle processor-type Function to control the data flow in your stream. 

Using this Function node helps to prevent a data overload in your stream. You place it appropriately in your stream to reduce the load sent to the following node(s).

Enter the number of transactions per second (TPS) that you want to permit. When setting the permitted TPS, bear in mind that if you send a large number of records to Throttle, and the node is set to a low level of TPS, you create a large queue. It is recommended that you set the TPS to a medium level relative to the number of records that you are processing.