set_session

# File actionpack/lib/action_dispatch/middleware/session/mem_cache_store.rb, line 37
        def set_session(env, sid, session_data)
          options = env['rack.session.options']
          expiry  = options[:expire_after] || 0
          @pool.set(sid, session_data, expiry)
          sid
        rescue MemCache::MemCacheError, Errno::ECONNREFUSED
          false
        end