set unacked_count and unacked_bytesize to 0 on queue restart

Author: viktorerlingsson

src/lavinmq/amqp/queue/queue.cr

@@ -220,6 +220,8 @@ module LavinMQ::AMQP
       @paused = BoolChannel.new(false)
       @consumers_empty = BoolChannel.new(true)
       @single_active_consumer_change = ::Channel(Client::Channel::Consumer).new
+      @unacked_count.set(0u32, :relaxed)
+      @unacked_bytesize.set(0u64, :relaxed)
     end
 
     # own method so that it can be overriden in other queue implementations