- updated _sidebar accordingly
- also commented out the "events with payload" section in the events cheatsheet

EventCounter.md

+If we want to check if how many events of each type have been posted, we can use the **EventCounter** class.  
+It is implemented as an [EventHandler](EventHandler).  
+It also need the reference to the [EventBroker](EventBroker), which has to be passed to the constructor.  
+In fact this class can subscribe to one or multiple topics and count how many times any event is posted to those topics: it keep the count both for the total number of events and the count for a single type of event.
+
+## Methods
+The available methods are:
+- **unsigned int getCount(const Event& ev)**: return how many times the specified event has been posted to the topics the event counter is subscribed to.
+- **unsigned int getCount(uint8_t ev_sig)**: return how many times the specified event has been posted to the topics the event counter is subscribed to.
+- **unsigned int getTotalCount()**: return how many events the event counter has received in total.
+
+You can find the complete implementation of the EventCounter in `src/shared/events/utils/EventCounter.h`.
+
+## Example
+This example shows the usage of the EventCounter using a single topic.  
+  
+First of all define the possible events and topics:
+```cpp
+#include <Common.h>
+#include "events/EventBroker.h"
+#include "events/utils/EventCounter.h"
+
+using namespace miosix;
+
+enum ExampleEvents : uint8_t
+{
+    EV_1 = EV_FIRST_SIGNAL,
+    EV_2
+};
+
+enum ExampleTopics : uint8_t
+{
+    TOPIC_1
+};
+```
+Then we can instantiate a new EventCounter and subscribe it to the existing topic `TOPIC_1`.  
+If we post some events, we can check how many events have been posted, both in total or for each event type:
+```cpp
+int main()
+{
+    EventCounter counter{*sEventBroker};
+    counter.subscribe(TOPIC_1);
+    Thread::sleep(100);
+
+    // post two events
+    sEventBroker->post(Event{EV_1}, TOPIC_1);
+    Thread::sleep(100);
+    sEventBroker->post(Event{EV_2}, TOPIC_1);
+    Thread::sleep(100);
+
+    // As a result we have 2 events in total
+    // 1 for type EV_1 and 1 for type EV_2
+    TRACE("Total : %d \n", counter.getTotalCount());
+    TRACE("EV_1 count : %d \n", counter.getCount(EV_1));
+    TRACE("EV_2 count : %d \n", counter.getCount(Event{EV_2}));
+
+    // The last event is EV_2, its id should be 5
+    // (which is EV_FIRST_SIGNAL + 1, as defined in the above enum)
+    TRACE("Last event : %d \n", counter.getLastEvent());
+
+    counter.stop();
+    sEventBroker->stop();
+
+    return 0;
+}
+```
+
+#### Output
+```sh
+0.42> Total : 2 
+0.43> EV_1 count : 1 
+0.44> EV_2 count : 1 
+0.45> Last event : 5
+```
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