The topology.Server type will require the following changes:

• Remove the context.Context argument from Connect, since it's not actually used
• Move the topo parameter from the NewServer method to the Connect method
  • This is necessary because Disconnect sets this to nil. If we can't reset it then a Server can no longer be connected usefully after it is disconnected
• Rename Connection to ConnectionLegacy
• Add a new method Connection that implements the Connection method of the driver.Server interface
• Make Server implement driver.ErrorProcessor to handle SDAM errors.
• Update Server to use topology.pool and return topology.Connection from Server.Connection and topology.connectionLegacy from Server.ConnectionLegacy.
• Implement a semaphore for max connections.
  • This used to be contained in the connection.Pool implementation, but it's simpler to have the topology.Server type track this now that the pool is a private type within the topology package.