fix(change-streams): don't copy irrelevant resume options

Author: mbroadst

lib/change_stream.js

@@ -272,10 +272,14 @@ class ChangeStreamCursor extends Cursor {
       if (this.options[optionName]) result[optionName] = this.options[optionName];
     }
 
-    if (this.resumeToken) {
-      Object.assign(result, { resumeAfter: this.resumeToken });
-    } else if (this.startAtOperationTime && maxWireVersion(this.server) >= 7) {
-      Object.assign(result, { startAtOperationTime: this.startAtOperationTime });
+    if (this.resumeToken || this.startAtOperationTime) {
+      ['resumeAfter', 'startAfter', 'startAtOperationTime'].forEach(key => delete result[key]);
+
+      if (this.resumeToken) {
+        result.resumeAfter = this.resumeToken;
+      } else if (this.startAtOperationTime && maxWireVersion(this.server) >= 7) {
+        result.startAtOperationTime = this.startAtOperationTime;
+      }
     }
 
     return result;