This is what was needed to support node's v0.3 API (specifically, the rename from sys to util). It remains backwards compatible with the v0.2 branch.
`Buffer#utf8Write(str)`, was private API, and seems to have been removed in Node >v0.3.0.
Using `Buffer#write(str, 'utf8')` is the preferred way, and remains backwards compatible.
Detect for 'util', and use it if it's there. Otherwise fall back to '…
This is the recommended check by isaacs.
Actually, because of this Node commit made a couple hours ago, 2415405 is no longer necessary. It doesn't hurt, nonetheless...