Multicast$-$Causal:

a$).$ In the figure below, message sends and receipts are shown. Assign causal timestamps to each event $($send$,$ receipt, and deliver$).$ Don$$t forget to list when messages are buffered, and when they are delivered. Messages are shown as Mi$.$ Initial timestamps are zeroes. You can either annotate the figure or write below figure. $($Don$$t forget to include event names against the timestamps!$)$

b$.)$ In a distributed system with causal multicast ordering, the multicast layer $$forgets$$ to buffer messages and instead passes the messages up to the application immediately after the multicast is received. Show a run where this buggy algorithm causes the application to experience a causality violation.