code: public GetMetricStatisticsRequest withExtendedStatistics(String... extendedStatistics) {
          if (this.extendedStatistics == null) {
              setExtendedStatistics(new com.amazonaws.internal.SdkInternalList<String>(extendedStatistics.length));
          }
          for (String ele : extendedStatistics) {
              this.extendedStatistics.add(ele);
          }
          return this;
      }
docs: <p>
  The percentile statistics. Specify values between p0.0 and p100. When calling <code>GetMetricStatistics</code>,
  you must specify either <code>Statistics</code> or <code>ExtendedStatistics</code>, but not both. Percentile
  statistics are not available for metrics when any of the metric values are negative numbers.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setExtendedStatistics(java.util.Collection)} or {@link #withExtendedStatistics(java.util.Collection)} if
  you want to override the existing values.
  </p>
  
  @param extendedStatistics
  The percentile statistics. Specify values between p0.0 and p100. When calling
  <code>GetMetricStatistics</code>, you must specify either <code>Statistics</code> or
  <code>ExtendedStatistics</code>, but not both. Percentile statistics are not available for metrics when
  any of the metric values are negative numbers.
  @return Returns a reference to this object so that method calls can be chained together.