code: public SignatureResponse sendSignatureRequest(SignatureRequest request) throws SignitException, IOException {
          if (request == null) {
              return null;
          }
          if (!auth.hasAccessTokenType() || !auth.hasAppId() || !auth.hasSecretKey()) {
              throw new SignitException("请完善开发者信息");
          }
          httpClient.withAuth(auth)
                  .withPostObject(request);
          if (!auth.hasAccessToken()) {
              getOauthData(auth.getAppId(), auth.getSecretKey(), auth.getAccessTokenType(), true);
          }
          return retrySendRequest();
      }
docs: 发送快捷签署请求.
  
  @param request
  快捷签署请求
  @return 快捷签署响应
  @throws SignitException
  易企签自定义异常
  @throws IOException
  数据流异常
  @since 1.0.0