[Protocol] Add guidance to send CloseProducer before sending Producer…

… in case of client side timeout (apache#12948)

site2/docs/developing-binary-protocol.md

@@ -179,6 +179,10 @@ messages to the broker, referring to the producer id negotiated before.
 
 ![Producer interaction](assets/binary-protocol-producer.png)
 
+If the client does not receive a response indicating producer creation success or failure,
+the client should first send a command to close the original producer before sending a
+command to re-attempt producer creation.
+
 ##### Command Producer
 
 ```protobuf
@@ -276,6 +280,11 @@ When receiving a `CloseProducer` command, the broker will stop accepting any
 more messages for the producer, wait until all pending messages are persisted
 and then reply `Success` to the client.
 
+If the client does not receive a response to a `Producer` command within a timeout,
+the client must first send a `CloseProducer` command before sending another
+`Producer` command. The client does not need to await a response to the `CloseProducer`
+command before sending the next `Producer` command.
+
 The broker can send a `CloseProducer` command to client when it's performing
 a graceful failover (eg: broker is being restarted, or the topic is being unloaded
 by load balancer to be transferred to a different broker).

site2/website-next/docs/developing-binary-protocol.md

@@ -182,6 +182,10 @@ messages to the broker, referring to the producer id negotiated before.
 
 ![Producer interaction](/assets/binary-protocol-producer.png)
 
+If the client does not receive a response indicating producer creation success or failure,
+the client should first send a command to close the original producer before sending a
+command to re-attempt producer creation.
+
 ##### Command Producer
 
 ```protobuf
@@ -285,6 +289,11 @@ When receiving a `CloseProducer` command, the broker will stop accepting any
 more messages for the producer, wait until all pending messages are persisted
 and then reply `Success` to the client.
 
+If the client does not receive a response to a `Producer` command within a timeout,
+the client must first send a `CloseProducer` command before sending another
+`Producer` command. The client does not need to await a response to the `CloseProducer`
+command before sending the next `Producer` command.
+
 The broker can send a `CloseProducer` command to client when it's performing
 a graceful failover (eg: broker is being restarted, or the topic is being unloaded
 by load balancer to be transferred to a different broker).