docs: public static MutableDouble fromExternal(final DoubleSupplier s, final DoubleConsumer c) {
          return new MutableDouble() {
              @Override
              public double getAsDouble() {
                  return s.getAsDouble();
              }
  
              @Override
              public Double get() {
                  return getAsDouble();
              }
  
              @Override
              public MutableDouble set(final double value) {
                  c.accept(value);
                  return this;
              }
          };
      }