code: @SuppressWarnings("unchecked")
  	public Q includeField(final String field) {
  		if (this.fields == null) {
  			this.fields = new HashSet<>();
  		}
  
  		if (field != null) {
  			this.fields.add(field);
  		}
  
  		return (Q) this;
  	}
docs: Specify a field to return in the results using the Fluent API approach. Users may specify this method multiple
  times to define the collection of fields they want returning, and/or use
  {@link SoundPagingQuery#includeFields(Set)} to  define them as a batch.
  
  @param field The field to include in the results
  @return The current query