anchor.diff:  IMPORTANT: The key that is used to store the assigned identifier should be indexed in the underlying graph database. If it is not indexed, then lookups for the elements that use these identifiers will perform a linear scan.
   
   EventStrategy
  -=============
  +~~~~~~~~~~~~~
   
   The purpose of the `EventStrategy` is to raise events to one or more `MutationListener` objects as changes to the underlying `Graph` occur within a `Traversal`. Such a strategy is useful for logging changes, triggering certain actions based on change, or any application that needs notification of some mutating operation during a `Traversal`.  Graphs that do not support transactions will generate events immediately upon mutation, while those graphs that support transactions will queue the mutations until that transaction is committed and will then raise the events.  If the transaction is rolled back, the event queue is reset.
   
  
positive.code: strategyA = PartitionStrategy.build().partitionKey("_partition").writePartition("a").addReadPartition("a").create()
  strategyB = PartitionStrategy.build().partitionKey("_partition").writePartition("b").addReadPartition("b").create()
  gA = GraphTraversalSource.build().with(strategyA).create(graph)
  gA.addV() //// this vertex has a property of {_partition:"a"}
  gB = GraphTraversalSource.build().with(strategyB).create(graph)
  gB.addV() //// this vertex has a property of {_partition:"b"}
  gA.V()
  gB.V()
  ----
  
negative.code: CAUTION: `EventStrategy` is not meant for usage in tracking global mutations across separate processes.  In other words, an mutation in what JVM process is not raised as an event in a different JVM process.  In addition, events are not raised when mutations occur outside of the `Traversal` context.
  
  PartitionStrategy
  ~~~~~~~~~~~~~~~~~
  
  image::partition-graph.png[width=325]
  
  `PartitionStrategy` partitions the vertices and edges of a graph into `String` named partitions (i.e. buckets, subgraphs, etc.). The idea behind `PartitionStrategy` is presented in the image above where each element is in a single partition (represented by its color). Partitions can be read from, written to, and linked/joined by edges that span one or two partitions (e.g. a tail vertex in one partition and a head vertex in another).
  
  