ot::MeshForwarder::GetTimeInQueueHistogram() const method

Gets the time-in-queue histogram for messages in the TX queue. Histogram of the time-in-queue of messages in the transmit queue is collected. The time-in-queue is tracked for direct transmissions only and is measured as the duration from when a message is added to the transmit queue until it is passed to the MAC layer for transmission or dropped. The histogram is returned as an array of `uint32_t` values with `aNumBins` entries. The first entry in the array (at index 0) represents the number of messages with a time-in-queue less than `aBinInterval`. The second entry represents the number of messages with a time-in-queue greater than or equal to `aBinInterval`, but less than `2 * aBinInterval`. And so on. The last entry represents the number of messages with time-in-queue greater than or * equal to `(aNumBins - 1) * aBinInterval`. The collected statistics can be reset by calling `ResetTimeInQueueStat()`. The histogram information is collected since the OpenThread instance was initialized or since the last time statistics collection was reset by calling the `ResetTimeInQueueStat()`.