Support retrieving all connections info from clients to mongodb, not just those running commands returned by currentOp(). OS command netstat can return all ip info, but it does not contain the relation ino between ip and database such database name and user. It's a common function in relation database, e.g. 'show processlist' command in mysql. And it's useful when we try to migrate to a new MongoDB cluster, we need to find out all the clients connected to the original mongodb.