docs: public TimeStats estimateTime(Object projectIdOrPath, Integer issueIid, Duration duration) throws GitLabApiException {
  
          if (issueIid == null) {
              throw new RuntimeException("issue IID cannot be null");
          }
  
          String durationString = (duration != null ? DurationUtils.toString(duration.getSeconds(), false) : null);
          GitLabApiForm formData = new GitLabApiForm().withParam("duration", durationString, true);
  
          Response response = post(Response.Status.OK, formData.asMap(),
                  "projects", getProjectIdOrPath(projectIdOrPath), "issues", issueIid, "time_estimate");
          return (response.readEntity(TimeStats.class));
      }