public default B addRegistries(final List<IoRegistry> registries) {
            B b = (B) this;
            for (final IoRegistry registry : registries) {
                b = this.addRegistry(registry);
            }
            return b;
        }
Adds a vendor supplied {@link IoRegistry} to the {@code Mapper.Builder} which enables it to check for
vendor custom serializers to add to the {@link Mapper}.  All {@link Io} implementations should expose
this method via this {@link Builder} so that it is compatible with {@link Graph#io}. Successive calls
to this method will add multiple registries.  Registry order must be respected when doing so.  In
other words, data written with {@link IoRegistry} {@code A} added first and {@code B} second must be read
by a {@code Mapper} with that same registry ordering.  Attempting to add {@code B} before {@code A} will
result in errors.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/Mapper.java