docs: public ApiResponse<MailResponse> getCharactersCharacterIdMailMailIdWithHttpInfo(Integer characterId,
              Integer mailId, String datasource, String ifNoneMatch, String token) throws ApiException {
          com.squareup.okhttp.Call call = getCharactersCharacterIdMailMailIdValidateBeforeCall(characterId, mailId,
                  datasource, ifNoneMatch, token, null);
          Type localVarReturnType = new TypeToken<MailResponse>() {
          }.getType();
          return apiClient.execute(call, localVarReturnType);
      }