Returns a specification to start this module under a supervisor.

See Supervisor.

@spec close_all_connections() :: :ok

Closes all connections.

@spec close_connection(pid()) :: :ok

Closes a specific connection.

@spec get_connection(ExUtcp.Types.mcp_provider()) ::
  {:ok, pid()} | {:error, String.t()}

Gets a connection for the given provider.

@spec start_link(keyword()) :: GenServer.on_start()

Starts the MCP connection pool.

@spec stats() :: map()

Gets pool statistics.