All heap access must be synchronized. Using pooled buffers may actually be faster because you can ensure that only one thread is accessing a specific pool. Just create a new pool, when a new thread is created.
Or, you know, each thread could allocate only when it needs something and handle its own recycling. Node.js has a particular advantage in that it isn't concurrent in any way (which, of course, has many other downsides.)
You can certainly build concurrent systems on top of Node, what it doesn't have is preemptive multi-threading, which sucks IMHO, but speaking of Go I also don't like that it does M:N multi-threading instead of 1:1 like the JVM, as the scheduling done is suboptimal.
