Pushed 2.4rc1

[Dustin]

Been a bit busy on other things, but I put together 2.4rc1 today,
and it's available in my mvn repo:

http://code.google.com/p/spymemcached/wiki/Maven

Prerelease of 2.4

Changes since the 2.3 series.

Bug Fixes:

* Memcached node tracking.
When a timeout occurs on an operation, the exception indicates the
server node that was the intendend recipient of the operation.
* Fixed reconnect loss on multiple simultaneous connection failures.
This is a rare occurrence, but the wrong thing would happen if two
simultaneous reconnects were requeued for any reason.
* Fixed a race condition that occurred when tearing down a connection.
There was a case where shutting down a connection would cause an NPE
to get logged due to the a race between a selector check and the
selector being shut down. Unlikely to affect a running app, but
it was still wrong.
* Handle initial connect failures.
There were rare cases where an async connect would error instantly
on the first attempt, but that connect wouldn't be retried.

Features:

* ConnectionFactoryBuilder
Rather than having to build a custom subclass of
DefaultConnectionFactory to override behaviors, you can now use a
ConnectionFactoryBuilder to easily assemble a ConnectionFactory as
you want it.
* Mutation-only CAS mutator
Previously, the CASMutator required an initial object to use if the
object you were attempting to mutate wasn't found. Now you can
specify this as NULL and CASMutator will *only* mutate an existing
object, but never create a new one.
* CacheLoader
CacheLoader provides a couple of convenient mechanisms for
efficiently loading bulk data. I've seen many benchmarks trying to
see how fast data can go into memcached through the client (as
opposed to normal usage), but they do things to make it
unnecessarily slow. This should satisfy both benchmarking
requirements and legitimate bulk loading requirements.

Performance Enhancements:

* Disable Nagle Algorithm by Default
The usage of the Nagle algorithm (tcpNoDelay) is now configurable
and is configured off by default (Nagle algorithm off = tcpNoDelay
on). This should be more optimal for most configurations.
* Multi-set Escalation in the Binary Protocol
With no changes to the API, multiple sequential sets will be
escalated into a multi-set operation similar to multi-get. In a
bulk load test, this is generally around 2x faster.
* Asynchronous Transcoding Service
A transcoder can request a transcoder service (effectively a
threadpool) to asynchronously decode cache response objects both
outside of the API and outside of the caller thread.

Contributors:

30 Dustin Sallings
1 Joseph Hart
1 Wang Nan