Hi, We're using mongo-driver 1.4.6 (golang) to talk to microsoft cosmos db (SDK version 3.6). However, recently, we experience issues. The program starts with everything fine, but after a while, it seems that somehow the program gets into a stack that all mongo request just timed out after 30 second. Here is the call stack. 

Once this happens, ALL mongo db request just timed out.

We don't know what triggered this condition to start though.
go.mongodb.org/mongo-driver/x/mongo/driver/topology.(*Topology).selectServerFromSubscription(0xc00056e8f0, 0x29b17a0, 0xc004a97d10, 0xc004582720, 0x296c700,
0xc000d8e6e0, 0xc0045826c0, 0xc0045826c0, 0x0, 0x0, ...)
/go/pkg/mod/go.mongodb.org/mongo-driver@v1.4.6/x/mongo/driver/topology/topology.go:435 +0x13c
go.mongodb.org/mongo-driver/x/mongo/driver/topology.(*Topology).SelectServer(0xc00056e8f0, 0x29b17a0, 0xc004a97d10, 0x296c700, 0xc000d8e6e0, 0x0, 0x0, 0x0, 0x0)
/go/pkg/mod/go.mongodb.org/mongo-driver@v1.4.6/x/mongo/driver/topology/topology.go:332 +0xfe
go.mongodb.org/mongo-driver/x/mongo/driver.Operation.selectServer(0xc0044e8c40, 0xc0014b68b0, 0xf, 0x297a9e0, 0xc00056e8f0, 0xc0044e8c50, 0x296c700, 0xc000d8e6e0, 0x39ddce0, 0xc00037dd30, ...)
/go/pkg/mod/go.mongodb.org/mongo-driver@v1.4.6/x/mongo/driver/operation.go:210 +0xd5
go.mongodb.org/mongo-driver/x/mongo/driver.Operation.Execute(0xc0044e8c40, 0xc0014b68b0, 0xf, 0x297a9e0, 0xc00056e8f0, 0xc0044e8c50, 0x296c700, 0xc000d8e6e0, 0x39ddce0, 0xc00037dd30, ...)
/go/pkg/mod/go.mongodb.org/mongo-driver@v1.4.6/x/mongo/driver/operation.go:238 +0xe5
go.mongodb.org/mongo-driver/x/mongo/driver/operation.(*Find).Execute(0xc000996380, 0x29b17a0, 0xc004a97d10, 0xc0007c8c00, 0x14)
/go/pkg/mod/go.mongodb.org/mongo-driver@v1.4.6/x/mongo/driver/operation/find.go:102 +0x22f
go.mongodb.org/mongo-driver/mongo.(*Collection).Find(0xc0045825a0, 0x29b17a0, 0xc004a97d10, 0x219eb80, 0xc000d8e3e0, 0xc001a43268, 0x1, 0x1, 0xc004a97d10, 0x30, ...)
/go/pkg/mod/go.mongodb.org/mongo-driver@v1.4.6/mongo/collection.go:1230 +0x669
github.com/getoutreach/azuresdk/cosmos.(*collection).getDocuments(0xc0009160f8, 0x29b17a0, 0xc004a979e0, 0x7f6a61b93518, 0xc004a97710, 0x29788e0, 0xc000d8e4c0, 0x495100, 0x0, 0x0)
/go/pkg/mod/github.com/getoutreach/azuresdk@v0.0.0-20210611003001-47584935650e/cosmos/collection.go:61 +0x233