fix: return consistent type

Author: nbbeeken

src/cmap/wire_protocol/responses.ts

@@ -126,6 +126,17 @@ function throwUnsupportedError() {
 
 /** @internal */
 export class CursorResponse extends MongoDBResponse {
+  static emptyGetMore = new CursorResponse(
+    Buffer.from(
+      'NgAAABBvawABAAAAA2N1cnNvcgAhAAAAEmlkAAAAAAAAAAAABG5leHRCYXRjaAAFAAAAAAAA',
+      'base64'
+    )
+  );
+
+  static override is(value: unknown): value is CursorResponse {
+    return value instanceof CursorResponse;
+  }
+
   public id: Long | null = null;
   public ns: MongoDBNamespace | null = null;
   public documents: any | null = null;
@@ -183,8 +194,4 @@ export class CursorResponse extends MongoDBResponse {
       push: { value: throwUnsupportedError }
     });
   }
-
-  static override is(value: unknown): value is CursorResponse {
-    return value instanceof CursorResponse;
-  }
 }

src/cursor/find_cursor.ts

@@ -110,7 +110,7 @@ export class FindCursor<TSchema = any> extends AbstractCursor<TSchema> {
           // instead, if we determine there are no more documents to request from the server, we preemptively
           // close the cursor
         }
-        return { cursor: { id: Long.ZERO, nextBatch: [] } };
+        return CursorResponse.emptyGetMore;
       }
     }