There appears to be a deadlock when trying to find files in GridFS using the Async method.

var client = new MongoClient("whatever_connection_str");
var database = client.GetDatabase("your_db");
var bucket = new GridFSBucket(database, new GridFSBucketOptions

);
var builder = Builders<GridFSFileInfo>.Filter;

// userid is embedded in the metadata of the fileinfo, confirmed it's there and correct type etc
var filter = builder.Eq(info => info.Metadata["UserId"], <any_object_id>);
var files = await bucket.FindAsync(filter); <-- this deadlocks in ASP.Net

If you try the same code in a console app it works fine.