add prefetch_count for amqp input
diff --git a/metadata/service/server/amqp/router.yml b/metadata/service/server/amqp/router.yml
index 3cc679f..5d910b2 100644
--- a/metadata/service/server/amqp/router.yml
+++ b/metadata/service/server/amqp/router.yml
@@ -14,6 +14,7 @@
           vhost: ${_param:heka_router_input_vhost}
           port: 5672
           exchange: ${_param:heka_router_input_exchange}
+          prefetch_count: ${_param:heka_router_input_prefetch_count}
           exchange_type: fanout
           decoder: ProtoBufDecoder
           splitter: HekaFramingSplitter