Typed tables, cannot run update operations that set map columns to empty

[sl-at-ibm]

Neither for typed nor for untyped can one run an update that sets a (non-string-keyed) map column to the empty map. Doing so results in the wrong serialization as [] instead of the required {}.

This affects:

Typed update via a dictionary, i.e.

            var mapIntStr_Typed_Empty = new Dictionary<int, string> { };

            var updateTyped_Empty = Builders<SBook>
              .TableUpdate.Set(b => b.MapColumnIntStr, mapIntStr_Typed_Empty);

            await table.UpdateOneAsync(filterUpd_Typed, updateTyped_Empty);

Untyped update via dictionary, i.e.

            var mapIntStr_Untyped_Empty = new Dictionary<int, string> { };

            var updateUntyped_Empty = Builders<Row>
              .TableUpdate.Set("map_column_int_str", mapIntStr_Untyped_Empty);

            await untypedTable.UpdateOneAsync(filterUpd_Untyped, updateUntyped_Empty);

_Note: this also happens for untyped updates done with a new List<object[]> { }, but those don't seem that they can be healed elegantly.