Fix incorrect message size; Use nio for decoding.

[nite23]

No description provided.

[jfarcand]

Thanks!

[Gekkio]

Sorry for intruding, but one thing caught my attention in this pull request:

What is the lifecycle of Interceptors? Are they created once and reused by multiple threads? If so, that code will break because CharsetDecoder/CharsetEncoder are not thread-safe. The class stores them in instance variables and reuses them in each call to transform().

[jfarcand]

@Gekkio Good catch! We need to fix that problem for sure.

[nite23]

@Gekkio Thanks for noticing. Here's a fix: ab841a6
I guess this would be better than synchronizing on the encoder/decoder...

[Gekkio]

Yeah, that fix works fine. It does create a bit more temporary objects than before, but that's the right way to do it since synchronizing would kill the performance.