code: public com.squareup.okhttp.Call getContractsPublicItemsContractIdAsync(Integer contractId, String datasource,
              String ifNoneMatch, Integer page, final ApiCallback<List<PublicContractsItemsResponse>> callback)
              throws ApiException {
  
          com.squareup.okhttp.Call call = getContractsPublicItemsContractIdValidateBeforeCall(contractId, datasource,
                  ifNoneMatch, page, callback);
          Type localVarReturnType = new TypeToken<List<PublicContractsItemsResponse>>() {
          }.getType();
          apiClient.executeAsync(call, localVarReturnType, callback);
          return call;
      }
docs: Get public contract items (asynchronously) Lists items of a public
  contract --- This route is cached for up to 3600 seconds
  
  @param contractId
  ID of a contract (required)
  @param datasource
  The server name you would like data from (optional, default to
  tranquility)
  @param ifNoneMatch
  ETag from a previous request. A 304 will be returned if this
  matches the current ETag (optional)
  @param page
  Which page of results to return (optional, default to 1)
  @param callback
  The callback to be executed when the API call finishes
  @return The request call
  @throws ApiException
  If fail to process the API call, e.g. serializing the request
  body object