Request for Comments 1122 states (of TCP):

A host MAY implement a “half-duplex” TCP close sequence, so that an application that has called CLOSE cannot continue to read data from the connection. If such a host issues a CLOSE call while received data is still pending in TCP, or if new data is received after CLOSE is called, its TCP SHOULD send an RST to show that data was lost.

Sketch a scenario involving the above in which data sent by (not to!)

the closing host are lost. You may assume that the remote host, upon receiving an RST, discards all received data still unread in buffers.