If by client ID you mean the tenant ID then that is 13e8af8d-a69b-4fb8-b6d3-102ee6fb2c31.
I do not know the request IDs for the above, so I created new requests and logged the received response headers. You can see the request ID in them. The timestamps are in the log entries below. They are in UTC. The scenario is the same as above. For each email, send an inline image, a PDF, and a word document.
2022-03-18 14:33:42.958 DEBUG 4143 --- [geMailService-0] n.i.a.g.c.e.a.i.m.impl.MsGraphApiImpl : Response headers
[Cache-Control:"private", Transfer-Encoding:"chunked", Content-Type:"application/json; odata.metadata=minimal; odata.streaming=true; IEEE754Compatible=false; charset=utf-8", Vary:"Accept-Encoding", Strict-Transport-Security:"max-age=31536000", request-id:"0e262ae6-c2df-4702-bf9e-5222744dbc76", client-request-id:"0e262ae6-c2df-4702-bf9e-5222744dbc76", x-ms-ags-diagnostic:"{"ServerInfo":{"DataCenter":"East US","Slice":"E","Ring":"5","ScaleUnit":"003","RoleInstance":"BL6PEPF0000F2F5"}}", Preference-Applied:"IdType=ImmutableId", Date:"Fri, 18 Mar 2022 14:33:43 GMT"]
2022-03-18 14:33:42.958 DEBUG 4143 --- [geMailService-0] n.i.a.g.c.e.a.i.m.impl.MsGraphApiImpl : Received attachments for message ID AAkALgAAAAAAHYQDEapmEc2byACqAC-EWg0AYwBZg9EnKUaPqnnD4hVqYgAAIMfBrQAA. Attachments = [Attachment(contentType=image/jpeg, name=Image1.jpg, size=32502), Attachment(contentType=application/pdf, name=SamplePDF1.pdf, size=3228), Attachment(contentType=application/msword, name=WordDoc1.doc, size=6854)]
2022-03-18 14:42:00.475 DEBUG 4143 --- [geMailService-0] n.i.a.g.c.e.a.i.m.impl.MsGraphApiImpl : Response headers
[Cache-Control:"private", Transfer-Encoding:"chunked", Content-Type:"application/json; odata.metadata=minimal; odata.streaming=true; IEEE754Compatible=false; charset=utf-8", Vary:"Accept-Encoding", Strict-Transport-Security:"max-age=31536000", request-id:"105d433f-7912-46e9-b872-e3bc31fe470f", client-request-id:"105d433f-7912-46e9-b872-e3bc31fe470f", x-ms-ags-diagnostic:"{"ServerInfo":{"DataCenter":"North Central US","Slice":"E","Ring":"3","ScaleUnit":"002","RoleInstance":"CH01EPF00009C6A"}}", Preference-Applied:"IdType=ImmutableId", Date:"Fri, 18 Mar 2022 14:42:00 GMT"]
2022-03-18 14:42:00.476 DEBUG 4143 --- [geMailService-0] n.i.a.g.c.e.a.i.m.impl.MsGraphApiImpl : Received attachments for message ID AAkALgAAAAAAHYQDEapmEc2byACqAC-EWg0AYwBZg9EnKUaPqnnD4hVqYgAAIMfFugAA. Attachments = [Attachment(contentType=image/jpeg, name=Image1.jpg, size=32502), Attachment(contentType=image/jpeg, name=Image2.jpg, size=59682), Attachment(contentType=application/pdf, name=SamplePDF2.pdf, size=69599), Attachment(contentType=application/msword, name=WordDoc2.doc, size=6854)]
2022-03-18 14:45:31.267 DEBUG 4143 --- [geMailService-0] n.i.a.g.c.e.a.i.m.impl.MsGraphApiImpl : Response headers
[Cache-Control:"private", Transfer-Encoding:"chunked", Content-Type:"application/json; odata.metadata=minimal; odata.streaming=true; IEEE754Compatible=false; charset=utf-8", Vary:"Accept-Encoding", Strict-Transport-Security:"max-age=31536000", request-id:"b0056c15-44c5-4123-b311-115ad6060014", client-request-id:"b0056c15-44c5-4123-b311-115ad6060014", x-ms-ags-diagnostic:"{"ServerInfo":{"DataCenter":"North Central US","Slice":"E","Ring":"3","ScaleUnit":"002","RoleInstance":"CH01EPF00009C6A"}}", Preference-Applied:"IdType=ImmutableId", Date:"Fri, 18 Mar 2022 14:45:30 GMT"]
2022-03-18 14:45:31.268 DEBUG 4143 --- [geMailService-0] n.i.a.g.c.e.a.i.m.impl.MsGraphApiImpl : Received attachments for message ID AAkALgAAAAAAHYQDEapmEc2byACqAC-EWg0AYwBZg9EnKUaPqnnD4hVqYgAAIMfF7AAA. Attachments = [Attachment(contentType=image/jpeg, name=Image1.jpg, size=32502), Attachment(contentType=image/jpeg, name=Image2.jpg, size=59682), Attachment(contentType=image/png, name=Image3.png, size=622385), Attachment(contentType=application/pdf, name=SamplePDF3.pdf, size=13464), Attachment(contentType=application/msword, name=WordDoc3.doc, size=6854)]
2022-03-18 14:49:34.510 DEBUG 4143 --- [geMailService-0] n.i.a.g.c.e.a.i.m.impl.MsGraphApiImpl : Response headers
[Cache-Control:"private", Transfer-Encoding:"chunked", Content-Type:"application/json; odata.metadata=minimal; odata.streaming=true; IEEE754Compatible=false; charset=utf-8", Strict-Transport-Security:"max-age=31536000", request-id:"ed10c479-e2ea-47b0-8043-a22c9f831d30", client-request-id:"ed10c479-e2ea-47b0-8043-a22c9f831d30", x-ms-ags-diagnostic:"{"ServerInfo":{"DataCenter":"North Central US","Slice":"E","Ring":"3","ScaleUnit":"000","RoleInstance":"CH01EPF00007835"}}", Preference-Applied:"IdType=ImmutableId", Date:"Fri, 18 Mar 2022 14:49:34 GMT"]
2022-03-18 14:49:34.510 DEBUG 4143 --- [geMailService-0] n.i.a.g.c.e.a.i.m.impl.MsGraphApiImpl : Received attachments for message ID AAkALgAAAAAAHYQDEapmEc2byACqAC-EWg0AYwBZg9EnKUaPqnnD4hVqYgAAIMfGCQAA. Attachments = [Attachment(contentType=image/jpeg, name=Image1.jpg, size=32502), Attachment(contentType=image/jpeg, name=Image2.jpg, size=59682), Attachment(contentType=image/png, name=Image3.png, size=622385), Attachment(contentType=image/png, name=Image4.png, size=285877), Attachment(contentType=application/pdf, name=SamplePDF4.pdf, size=8145), Attachment(contentType=application/msword, name=WordDoc4.doc, size=6854)]