private com.google.protobuf.SingleFieldBuilder<
          org.box2d.proto.Box2D.PbVec2, org.box2d.proto.Box2D.PbVec2.Builder, org.box2d.proto.Box2D.PbVec2OrBuilder> 
          getLocalAnchorBFieldBuilder() {
        if (localAnchorBBuilder_ == null) {
          localAnchorBBuilder_ = new com.google.protobuf.SingleFieldBuilder<
              org.box2d.proto.Box2D.PbVec2, org.box2d.proto.Box2D.PbVec2.Builder, org.box2d.proto.Box2D.PbVec2OrBuilder>(
                  localAnchorB_,
                  getParentForChildren(),
                  isClean());
          localAnchorB_ = null;
        }
        return localAnchorBBuilder_;
      }