About the problem that the mongodb driver count method of rust cannot be used with the near condition

I recently used mongodb in my own project, and encountered a strange problem, that is, if the rust mongodb driver is used to operate mongodb, when using the db.collection.count() method, if the query condition contains$near,\; it\; will\; report\text{'}$geoNear, $near, and $nearSphere are not allowed in this context`, there is no beginning or end in a sentence, and I can't figure out what the context mentioned here specifically refers to. I searched the Internet, and there is relatively little relevant information, most of which are not available.The positive answer is where the problem is, and there are fewer solutions.No way, I can only try it myself. You can successfully get the return value by executing the query through the mongo shell, so it can be basically determined that it is the problem of the mongodb driver of rust. The current version is 2.3.0, which is the latest one. SolvedThe only way to save the country is to save the country through the curve, change db.collection.count() to db.collection.find(), because db.collection.find() returns a Stream, and the futures crate provides an extension to Stream(StreamExt), which includes a count() method, which we can call directly to get the count.

But note, Because Stream is essentially an Iterator, so our count is really obtained by traversing the entire result set, whether in terms of time or resource overhead, the cost isVery high, because my application scenario generally does not count more than 7, so I can barely accept it, if the count is larger, please find another way