Add walkthrough comments explaining log-vs-failure for nil records

Explains why post-delete SOQL/SOSL verification uses NSLog instead of
XCTAssertNotNil: delete already asserted success, queryAll verifies
recycle bin, and these steps only check index consistency. A hard
assertion caused ~1-in-10 CI flakes.

Author: JohnsonEricAtSalesforce

libs/SalesforceSDKCore/SalesforceSDKCoreTests/SalesforceRestAPITests.m

@@ -654,23 +654,29 @@ - (void)testCreateQuerySearchDelete {
         }
     }
 
-    // well, let's do another query just to be sure — use retry since SOQL can briefly show stale results after delete
+    // Post-delete verification: confirm SOQL no longer returns the record.
+    // If records is nil, the server was unreachable during the entire polling window.
+    // We log rather than fail because: (1) delete already asserted success in @finally above,
+    // (2) queryAll below separately verifies the record is in the recycle bin, and
+    // (3) this step only checks index consistency — not SDK correctness.
+    // A hard assertion here caused ~1-in-10 CI flakes when SOQL was transiently unreachable.
     request = [[SFRestAPI sharedInstance] requestForQuery:[NSString stringWithFormat:@"select Id, FirstName from Contact where LastName='%@'", lastName] apiVersion:kSFRestDefaultAPIVersion];
     NSArray *records = [self sendSyncQueryRequestUntilEmpty:request maxWaitSeconds:30];
     if (records) {
         XCTAssertEqual((int)[records count], 0, @"expected no result");
     } else {
         NSLog(@"[testCreateQuerySearchDelete] SOQL poll never got a valid response — server may have been briefly unreachable during post-delete verification");
     }
-    
+
     // check the deleted object is here
     request = [[SFRestAPI sharedInstance] requestForQueryAll:[NSString stringWithFormat:@"select Id, FirstName from Contact where LastName='%@'", lastName] apiVersion:kSFRestDefaultAPIVersion];
     response = [self sendSyncRequest:request];
     XCTAssertEqualObjects(response.returnStatus, kTestRequestStatusDidLoad, @"queryAll request failed");
     NSArray* records2 = ((NSDictionary *)response.dataResponse)[RECORDS];
     XCTAssertEqual((int)[records2 count], 1, @"expected just one query result");
 
-    // now search object — use retry since SOSL de-indexing has server-side lag
+    // Post-delete SOSL verification: same rationale as SOQL above.
+    // SOSL de-indexing has additional server-side lag beyond SOQL consistency.
     request = [[SFRestAPI sharedInstance] requestForSearch:[NSString stringWithFormat:@"Find {%@}", lastName] apiVersion:kSFRestDefaultAPIVersion];
     records = [self sendSyncSearchRequestUntilEmpty:request maxWaitSeconds:45];
     if (records) {