anchor.diff:  -record(state, {nodes     :: [{host(), inet:port_number()}],
                   username  :: binary(),
                   password  :: binary(),
  +                keyspace  :: binary(),
                   transport :: tcp | ssl,
                   socket    :: inet:socket(),
                   receiver  :: pid(),
  
positive.code:     init_opt(Opts, State#state{username = bin(Username)});
  init_opt([{password, Password}| Opts], State) ->
      init_opt(Opts, State#state{password = bin(Password)});
  init_opt([ssl | Opts], State) ->
      ssl:start(), % ok?
      init_opt(Opts, State#state{transport = ssl});
  
negative.code: -type option() :: {nodes,    [{host(), inet:port_number()}]}
                  | {username, binary()}
                  | {password, binary()}
                  | {keyspace, binary()}
                  | {ssl,      boolean()}
                  | {ssl_opts, [ssl:ssl_option()]}
                  | {timeout,  timeout()}
  