use bigint for cursor id

Author: baileympearson

src/cmap/wire_protocol/responses.ts

@@ -232,7 +232,7 @@ export class CursorResponse extends MongoDBResponse {
    * It is an optimization to avoid an extra getMore when the limit has been reached
    */
   static get emptyGetMore(): CursorResponse {
-    return new CursorResponse(serialize({ ok: 1, cursor: { id: 0, nextBatch: [] } }));
+    return new CursorResponse(serialize({ ok: 1, cursor: { id: 0n, nextBatch: [] } }));
   }
 
   static override is(value: unknown): value is CursorResponse {
@@ -247,12 +247,8 @@ export class CursorResponse extends MongoDBResponse {
   }
 
   public get id(): Long {
-    if (!this.cursor.has('id')) {
-      throw new MongoUnexpectedServerResponseError('"id" is missing');
-    }
     try {
-      const cursorId = this.cursor.get('id', BSONType.long, false);
-      return cursorId != null ? Long.fromBigInt(cursorId) : Long.fromBigInt(0n);
+      return Long.fromBigInt(this.cursor.get('id', BSONType.long, true));
     } catch (cause) {
       throw new MongoUnexpectedServerResponseError(cause.message, { cause });
     }