upadte esp mqtt client

lib/espMqttClient/docs/index.md

@@ -312,11 +312,13 @@ Publish a packet with a callback for payload handling. Return the packet ID (or
 The callback has the following signature: `size_t callback(uint8_t* data, size_t maxSize, size_t index)`. When the library needs payload data, the callback will be invoked. It is the callback's job to write data indo `data` with a maximum of `maxSize` bytes, according the `index` and return the amount of bytes written.
 
 ```cpp
-void clearQueue()
+void clearQueue(bool deleteSessionData = false)
 ```
 
-When disconnected, clears all queued messages.
-Keep in mind that this also deletes any session data and therefore is no MQTT compliant.
+Clears all queued messages.
+Keep in mind that this may also delete any session data and therefore is not MQTT compliant.
+
+- **`deleteSessionData`**: When true, delete all outgoing messages. Not MQTT compliant!
 
 ```cpp
 void loop()
@@ -361,12 +363,19 @@ Set this to 1 if you use the async version on ESP8266. For the regular client th
 ### EMC_ALLOW_NOT_CONNECTED_PUBLISH 1
 
 By default, you can publish when the client is not connected. If you don't want this, set this to 0.
+Regardless of this setting, after you called `disconnect()`, no messages can be published until fully disconnected.
+
+### EMC_WAIT_FOR_CONNACK 1
+
+espMqttClient waits for the CONNACK (connection acknowledge) packet before starting to send other packets.
+The MQTT specification allows to start sending before the broker acknowledges the connection but some brokers
+don't allow this (AWS for example doesn't).
 
 ### EMC_CLIENTID_LENGTH 18 + 1
 
 The (maximum) length of the client ID. (Keep in mind that this is a c-string. You need to have 1 position available for the null-termination.)
 
-### EMC_TASK_STACK_SIZE 5000
+### EMC_TASK_STACK_SIZE 5120
 
 Only used on ESP32. Sets the stack size (in words) of the MQTT client worker task.