Connections are leaking. Most likely related to https://github.com/mongodb/mongo-go-driver/commit/99bdb9492372cbf681e337926aca708bb3319076

File x/mongo/driver/topology/server.go
```
if isStreamingEnabled(s) && isStreamable(s) && !s.rttMonitor.started

```
Here is a call to s.rttMonitor.started without a mutex. Which can lead to calling multiple connection methods.

Detailed steps to reproduce the problem?

Include full traceback, if possible

Definition of done: what must be done to consider the task complete?

The exact Go version used, with patch level:

$ go version 

1.21

The exact version of the Go driver used:

$ go list -m go.mongodb.org/mongo-driver

go.mongodb.org/mongo-driver v1.15.0

Describe how MongoDB is set up. Local vs Hosted, version, topology, load balanced, etc.

replica set, 3 hosts

1. mongod --version
   db version v6.0.6
   Build Info: {
       "version": "6.0.6",
       "gitVersion": "26b4851a412cc8b9b4a18cdb6cd0f9f642e06aa7",
       "openSSLVersion": "OpenSSL 1.1.1f  31 Mar 2020",
       "modules": [],
       "allocator": "tcmalloc",
       "environment": {         "distmod": "ubuntu2004",         "distarch": "x86_64",         "target_arch": "x86_64"     }

   }

   The operating system and version (e.g. Windows 7, OSX 10.8, ...)

Ubuntu 20.04.6 LTS (Focal Fossa)

Security Vulnerabilities

If you’ve identified a security vulnerability in a driver or any other MongoDB project, please report it according to the instructions here