Who is the real beneficiary and sponsor of this act? It is China who has got this act done through the ISI of Pakistan as a cross favor for CPEC and Masood Azhar, who in turn have used their Jihadi network to execute it in Sri Lanka.
Why China? Because with this act of "Supari to Pakistan", it is trying to flex its muscles by putting economic and financial pressure on Sri Lanka as a consequence of this terrorism act. Sri Lanka may have asked China to comply strictly to economic use of Hambantota port against China's wishes of expanded use for covert and military purpose.
It would be wise for Sri Lanka to restrict any Chinese or Pakistani presence on their land, instead ask them to use locals for all commercial activity China want to execute on Hambantota port