The statistics are available in the “monitor” section of the API. To get statistics about a flow, you can send semp request https://broker-ip/SEMPv2/monitor/{msgVpnName}/queues/{queueName}/txFlows/{flowId}
Items in the response will include:
activationTmie
activityState
bindTime
maxUnackedMsgsExceededMsgCount
redeliveredMsgCount
redeliveryRequestCount
selectorExaminedMsgCount
etc.
Please see:
SEMP API Reference, scroll down to the Code 200 section and click on “MsgVpnQueueTxFlowResponse” and then “MsgVpnQueueTxFlow” for more information about what is returned.