This is done by only truncating the read buffer once a full reply has
been read. The buffer is no longer truncated halfway through reading a
reply. In addition: pass offset/length of protocol and content via the
read tasks.
The libevent example cannot be compiled when -std=c99 is passed. It is
not necessary that the adapters nor the examples follow this standard,
as long as the code for hiredis itself is compliant.