How request node handle snoop transaction before it receives DataSepResp of last transaction in CHI specification?

Hi,

     In CHI specification, request node can send out CompAck after it receives RespSepData and before it recieves DataSepResp.

     Let us consider the following scenario:

     Step 1: Request node_A wants to write address_B, but its cache doesn't have data of address_B.

     Step 2: Request node_A sends out ReadUnique request message to get data of address_B.

     Step3: Home node returns RespSepData response to request node_A.

     Step4: Home node returns DataSepResp to request node_A.  Assume RespSepData reaches request node_A soon, but DataSepResp takes very long time to travel to request node_A.

     Step5: Request node_A receives RespSepData and sends out CompAck to home node.

     Step6: Home node receives CompAck and sends out a snoop transaction to request node_A to read data of address_B. 

     Step7. Request node_A receives snoop request message but doesn't receives DataSepResp of ReadUnique transaction yet.

     Now, snoop transaction wants to read data of address_B, but data of address_B is on the way to request node_A, request node_A doesn't have data of address_B yet.  How does request node_A handle this snoop transaction? Anyone know it? Thanks a lot.