code: public long getRateLimitReset()
      {
          if (retrofitError.getResponse() == null)
          {
              return -1;
          }
          for (Header header : retrofitError.getResponse().getHeaders())
          {
              if ("X-RateLimit-Reset".equals(header.getName()))
              {
                  return Long.parseLong(header.getValue());
              }
          }
          return -1;
      }
docs: Return the number of seconds before the rate limit resets, or <code>-1</code> if the exception was not
  the result of a HTTP 429 Too Many Requests rate limit error.
  
  @since 1.5
  @see #isRateLimitError
  @return the number of seconds before the rate limit resets, or <code>-1</code> if the exception was not
  the result of a HTTP 429 Too Many Requests rate limit error