def command(command)
      read_preference.with_node(cluster) do |node|
        node.command(name, command, query_options({}))
      end
    end
def command(command)
      read_preference.with_node(cluster) do |node|
        node.command(name, command, query_options({}))
      end
    end
Run +command+ on the database.

 @example Run a command.
   db.command(ismaster: 1)
   # => { "master" => true, hosts: [] }

 @param [ Hash ] command The command to run.

 @return [ Hash ] the result of the command.

 @since 1.0.0