1. A method for receiving versions of state objects at one or more stages in a processing pipeline, the method comprising; receiving a first version of a state object at a first stage in the processing pipeline, wherein the first version of the state object is included in a plurality of different versions of the state object; determining that the first version of the state object is relevant to the first stage; incrementing a first reference counter associated with the first version of the state object; assigning the first version of the state object to work requests that arrive at the first stage subsequent to the receipt of the first version of the state object; and transmitting the first version of the state object to a second stage in the processing pipeline.