while fetching documents from a collection, why don't we allow to fetch specific fields only ?

[sanjaykj]

in below code, I want to be able to select a specific document property, so that only that is retrieved over the network. My primary goal is to reduce the data transferred through network.

final docRef = FirebaseFirestore.instance
    .collection('collection_name')
    .where('field1', isEqualTo: value)
    _**// .select(['field2']);    ----- uncommenting this line is throwing error.**_

_subscription = docRef.snapshots().listen(updateResultsToUI);

it seems selecting specific properties is not allowed in flutter. Is there a reason for that ? or am i missing something here ? Please advise.