code: public StartTaskRequest withContainerInstances(String... containerInstances) {
          if (this.containerInstances == null) {
              setContainerInstances(new com.amazonaws.internal.SdkInternalList<String>(containerInstances.length));
          }
          for (String ele : containerInstances) {
              this.containerInstances.add(ele);
          }
          return this;
      }
docs: <p>
  The container instance IDs or full ARN entries for the container instances on which you would like to place your
  task. You can specify up to 10 container instances.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setContainerInstances(java.util.Collection)} or {@link #withContainerInstances(java.util.Collection)} if
  you want to override the existing values.
  </p>
  
  @param containerInstances
  The container instance IDs or full ARN entries for the container instances on which you would like to
  place your task. You can specify up to 10 container instances.
  @return Returns a reference to this object so that method calls can be chained together.