increase main task stack size and mqtt buffer size

sphinx-key/sdkconfig.defaults

@@ -1,5 +1,5 @@
 # Rust often needs a bit of an extra main task stack size compared to C (the default is 3K)
-CONFIG_ESP_MAIN_TASK_STACK_SIZE=13000
+CONFIG_ESP_MAIN_TASK_STACK_SIZE=24000
 
 # Use this to set FreeRTOS kernel tick frequency to 1000 Hz (100 Hz by default).
 # This allows to use 1 ms granuality for thread sleeps (10 ms by default).

sphinx-key/src/conn/mqtt.rs

@@ -28,7 +28,7 @@ pub fn make_client(
     log::info!("make_client with id {}", client_id);
     let conf = MqttClientConfiguration {
         client_id: Some(client_id),
-        buffer_size: 2048,
+        buffer_size: 4096,
         task_stack: 12288,
         username: Some(USERNAME),
         password: Some(PASSWORD),