statechart
Declare and install this agent's statechart in one step. May be called at most once per agent (use buildStatechart + useStatechart for the multi-variant case). If the simulation is already running (runtime creation), the chart starts immediately; otherwise AgentModel.initialize starts it at the beginning of each replication.
Optional statechart governing this agent's reactive behavior. Default null for AgentLike implementations that don't provide a statechart abstraction. The concrete agent types (AgentModel.Agent, AgentModel.PermanentAgent, AgentResource) each override this with their own backing field.