core: handle._handle.close(callback) is not idempotent
handle._handle.close(callback)
is not idempotent and that's because node::HandleWrap::Close()
overrides the .close method with the callback. This one-liner should print 'Trace' only once:
$ iojs -e 'var t = new (process.binding("timer_wrap").Timer); t.close(console.trace); t.close()'
Trace
at [eval]:1:78
at Object.exports.runInThisContext (vm.js:54:17)
at Object.<anonymous> ([eval]-wrapper:6:22)
at Module._compile (module.js:410:26)
at evalScript (node.js:475:25)
at startup (node.js:84:9)
at node.js:867:3
Trace