code: public static MutableBoolean fromExternal(final BooleanSupplier s, final Consumer<Boolean> c) {
          return new MutableBoolean() {
              @Override
              public boolean getAsBoolean() {
                  return s.getAsBoolean();
              }
  
              @Override
              public Boolean get() {
                  return getAsBoolean();
              }
  
              @Override
              public MutableBoolean set(final boolean value) {
                  c.accept(value);
                  return this;
              }
          };
      }
docs: Construct a MutableBoolean that gets and sets an external value using the provided Supplier and Consumer
  
  e.g.
  <pre>
  {@code
  MutableBoolean mutable = MutableBoolean.fromExternal(()->!this.value,val->!this.value);
  }
  </pre>
  
  
  @param s Supplier of an external value
  @param c Consumer that sets an external value
  @return MutableBoolean that gets / sets an external (mutable) value