Updated kafka client (producer and consumer)

In our environment we use currently use Kafka 0.7.1.

The core features I am looking for in a client are this:

1. Provide confirmation of produce requests (or notification of
disconnection during requests).
2. Uses asynchronous IO so that:
A. Multiple ops can be queued/in-flight at once.
B. Fetch #2 can be in-flight while fetch #1 is being processed (without
requiring an extra thread per consumer)
3. Allow precise control of offsets (like the SimpleConsumer).

I have been working on a version of the Kafka client that meets those
requirements. However, I recall hearing talk of rewriting the client. Did
this happen as part of 0.8.x? If so, how different is it from the 0.7.x
clients, and how well would it support the requirements listed above?

Thanks in advance!

--Tom