code: private static StringBuilder reuseOrCreate(final StringBuilder builder, final int capacity) {
  		if (builder == null) {
  			return new StringBuilder(capacity);
  		} else {
  			builder.setLength(0);
  			return builder;
  		}
  	}
docs: Clears an existing string builder or creates a new one if given string builder is {@code null}.
  
  @param builder
  String builder instance or {@code null}
  @param capacity
  Initial capacity for new string builder if created
  @return Empty string builder