Create item with discard preprocessing, then send many same large values to it and notice that there is no vps in Zabbix server health template and no indication at all that there were many values processed by preprocessing manager, it makes it hard to understand what is going on when preprocessing manager memory suddenly rises such as in ZBX-25050

Expected:
There is internal item zabbix[preprocessing] that can be used to see that preprocessing manager received values and real throughput (please see "Preprocessor throughput in dashboard) it would be counter that always gets increased by size of received data by preprocessing manager, also see patch preprocessing_size_7_0.diff

Possible key:

zabbix[preprocessing]

The statistics of preprocessing manager.

• queued - the number and size of queued values that require preprocessing (counter)
• direct - the number and size of values that did not require preprocessing (counter)
• queue - The count of values enqueued in the preprocessing queue (same as zabbix[preprocessing_queue])

JSON:

{
        "queued": {
                "count": 0,
                "size": 0
        },
        "direct": {
                "count": 0,
                "size": 0
        },
        "queue": 0
}