Inside callback's angle brackets write "Response" and then extract the stream from this response.
service.getToto("toto", new Callback<Response>() {
@Override
public void success(Response result, Response response) {
//Try to get response body
BufferedReader reader = null;
StringBuilder sb = new StringBuilder();
try {
reader = new BufferedReader(new InputStreamReader(result.getBody().in()));
String line;
try {
while ((line = reader.readLine()) != null) {
sb.append(line);
}
} catch (IOException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
String result = sb.toString();
}
@Override
public void failure(RetrofitError error) {
}
});