Man pages matching name tshttptxnclientpackettosset in section 3ts:

TSHttpTxnClientPacketTosSet.3ts.en	debian 10 / trafficserver-dev
TSHttpTxnClientPacketTosSet.3ts.en	debian 11 / trafficserver-dev
TSHttpTxnClientPacketTosSet.3ts.en	debian 12 / trafficserver-dev