15. The computer program product of claim 13 , wherein the computer readable program, when executed on the computing device, further causes the computing device to: responsive to receiving a given file fragment of the file from the background swarm, store an identification of the given file fragment in a data structure.
15. The computer program product of claim 13 , wherein the computer readable program, when executed on the computing device, further causes the computing device to: responsive to receiving a given file fragment of the file from the background swarm, store an identification of the given file fragment in a data structure. 16. The computer program product of claim 15 , wherein identifying the at least one file fragment stored locally comprises: examining the data structure for file fragments identified as being stored locally.