let coll = conn.collection("collection");

let filter = doc! { "_id": id };
let update = doc! { "$set": {"meta": meta_data, "players": players } };
match coll.find_one_and_update(filter, update, None) {
    Ok(_result) => (),
    Err(e) => println!("Mongodb error: {:?}", e),
}

===> Mongodb error: Error { kind: CommandError(CommandError { code: 9, code_name: "FailedToParse", message: "Either an update or remove=true must be specified", labels: [] }) }