MultimapBuilder creates unnecessary objects

[CodingFabian]

Looking at high memory usage in one of our components, we noticed that for every MultiMap created by a MultimapBuilder, we have a Supplier too (in our case it is a HashSetSupplier, but it applies to other Suppliers too)

the reason for that is that we do:

  public static final MultimapBuilder.SetMultimapBuilder<Object, Object> RELATIONS_MAP_BUILDER = MultimapBuilder
      .hashKeys(2)
      .hashSetValues(1);

which in turn calls this Guava code

    public SetMultimapBuilder<K0, Object> hashSetValues(final int expectedValuesPerKey) {
      checkNonnegative(expectedValuesPerKey, "expectedValuesPerKey");
      return new SetMultimapBuilder<K0, Object>() {
        @Override
        public <K extends K0, V> SetMultimap<K, V> build() {
          return Multimaps.newSetMultimap(
              MultimapBuilderWithKeys.this.<K, V>createMap(),
              new HashSetSupplier<V>(expectedValuesPerKey));
        }
      };
    }

This creates a new hashSetSupplier every time build is invoked.
This looks incorrect to me, and the suppliers should be properties of the newly returned builder, shouldn't they?

[CodingFabian]