The Flush Spread project focuses on providing view synchrony group communication semantics built on top of Spread's extended virtual synchrony semantics. Currently, these semantics are provided by a client library that links with Spread's client library.
Obviously you need Spread for Flush Spread to work ... so go check out Spread.
Flush Spread includes a distribution of the Stdutil library, which is a toolkit of high-performance C data structures and utility functions. If you are interested, you can learn more about it here.