It seems that `buffer.toString("binary")` is deprecated and should be avoided: http://docs.nodejitsu.com/articles/advanced/buffers/how-to-use-buffers

`"binary": This is the "binary string" format mentioned earlier, and is in the process of being deprecated. Avoid its use.`

How about using `String.fromCharCode.apply(String, buffer)` instead? Can you check on how fast it can be?