Use of a Read Write Mutex

[shashankmehra]

I was wondering if this library supports concurrency, and saw that a recent commit seems to imply that the support has been added: 1ce4922

However, wouldn't your trie still be open to concurrent read operations while you have mutex locked Add or Remove. In that case, would it make sense to shift to sync.RWMutex.

Also to support custom concurrent walks, it would make sense to have GetChild(rune) *Node function instead of Children() map[rune]*Node. So that a read lock can be taken inside GetChild. Whereas, using Children() would allow the caller to easily ignore an internal mutex lock.