Fix wrong this context in QueryCursor._read cursor close callback

[techcodie]

Fix wrong this context in QueryCursor._read cursor close callback

Problem:
In QueryCursor.prototype._read, the cursor.close() callback used a regular function, causing this to be undefined. This meant any error during cursor close would fail silently instead of being emitted on the QueryCursor instance.

Fix:
Changed the regular function to an arrow function so this correctly refers to the QueryCursor instance - consistent with how AggregationCursor._read already handles it.

// Before
this.cursor.close(function(error) {
  if (error) {
    return this.emit('error', error); // `this` is wrong here
  }
});

// After
this.cursor.close((error) => {
  if (error) {
    return this.emit('error', error); // `this` correctly refers to QueryCursor
  }
});

Note: AggregationCursor._read already handles this correctly using _this. This PR makes QueryCursor consistent with that pattern.

[techcodie]

The failing test (sessions gh-6362 - sets session when pulling a document from db) is a pre-existing flaky timing test unrelated to this change. It checks session.serverSession.lastUse timestamps which can fail intermittently based on server response timing. Our change is limited to a one-line fix in queryCursor.js.

[vkarpov15]

Thanks 👍

[Copilot]

Pull request overview

Updates QueryCursor stream end-of-cursor handling to use an arrow function for the cursor.close() callback, ensuring the callback retains the QueryCursor instance context when emitting errors.

Changes:

• Replace function(error) with (error) => { ... } in the cursor.close() callback within _read()