1. A method comprising: receiving a first request for data associated with a first data identifier from a first requesting entity; maintaining mapping information for the first request that associates the first data identifier with the first requesting entity; receiving a second request for the data associated with the first data identifier from a second requesting entity; maintaining mapping information for the second request that associates the first data identifier with the second requesting entity; determining that the first data identifier applies to the first request and to the second request; requesting the data associated with the first data identifier from a data-providing entity in a multiplexed request; receiving a response to the multiplexed request from the data-providing entity, the response including the data associated with the first data identifier; returning a first response to the first request, including accessing the mapping information to include the data associated with the first data identifier in the first response; returning a second response to the second request, including accessing the mapping information to include the data associated with the first data identifier in the second response; adding the first data identifier to a pending set, and wherein determining that the first data identifier applies to the first request and the second request comprises detecting the first data identifier in the pending set as being present in the second request; and determining that no other request needs a response that includes the data associated with the first data identifier, and removing the first data identifier from the pending set.