retrofit/src/main/java/retrofit2/Response.java
public static <T> Response<T> success(@Nullable T body) {
    return success(body, new okhttp3.Response.Builder() //
        .code(200)
        .message("OK")
        .protocol(Protocol.HTTP_1_1)
        .request(new Request.Builder().url("http://localhost/").build())
        .build());
  }
public static <T> Response<T> success(@Nullable T body) {
    return success(body, new okhttp3.Response.Builder() //
        .code(200)
        .message("OK")
        .protocol(Protocol.HTTP_1_1)
        .request(new Request.Builder().url("http://localhost/").build())
        .build());
  }
Create a synthetic successful response with {@code body} as the deserialized body.