code: function resolve(state, key, cb) {
  	logger.debug('Resolving session', key);
  
  	var actorId, sessionKey;
  
  	try {
  		var parsed = parseKey(key);
  		actorId = parsed.actorId;
  		sessionKey = parsed.sessionKey;
  	} catch (e) {
  		emitUnset(state, e.message);
  		return cb();
  	}
  
  	getActorSession(state, actorId, function (error, session) {
  		if (error) {
  			return cb(error);
  		}
  
  		try {
  			assert(session, 'noSession');
  			assert.equal(session.key, sessionKey, 'keyMismatch');
  			assert(sessionHasSupportedVersion(session), 'badVersion');
  		} catch (e) {
  			emitUnset(state, e.message);
  			return cb();
  		}
  
  		logger.debug('Session resolves successfully, pushing expiration time into the future');
  
  		session.extend(state);
  
  		return cb(null, session);
  	});
  }
docs: resolve(key) returns a session object to the callback for the given key