These two structures represent a way to abstract the implementation details of the graph structure that is being used for the different pieces of code related to compiling Niagara systems. The GraphBridge handles the standard editor objects for graphs & nodes (UNiagaraGraph and UNiagaraNode respectively) with the remaining types following from that. The DigestBridge represents the digested graphs and nodes that we use to be able to compile Niagara systems async where the graphs & nodes are FNiagaraCompilationGraphFNiagaraCompilationNode respectively.