public Builder registrationRequired(final boolean registrationRequired) {
            this.registrationRequired = registrationRequired;
            return this;
        }
When set to {@code true}, all classes serialized by the {@code Kryo} instances created from this
{@link GryoMapper} must have their classes known up front and registered appropriately through this
builder.  By default this value is {@code true}.  This approach is more efficient than setting the
value to {@code false}.

@param registrationRequired set to {@code true} if the classes should be registered up front or
                            {@code false} otherwise
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/gryo/GryoMapper.java