A generalized custom serializer registry for providers implementing a 
Graph.  Providers should develop an
 implementation of this interface if their implementation requires custom serialization of identifiers or other
 such content housed in their graph.  Consider extending from 
AbstractIoRegistry and ensure that the
 implementation has a zero-arg constructor or a static "instance" method that returns an 
IoRegistry
 instance, as implementations may need to be constructed from reflection given different parts of the TinkerPop
 stack.
 
 The serializers to register depend on the 
Io implementations that are expected to be supported.  There
 are currently two core implementations in 
GryoIo and 
GraphSONIo.  Both of these should be supported
 for full compliance with the test suite.
 
 There is no need to use this class if the 
Graph does not have custom classes that require serialization.