Cache expensive begin and end calls in DiscreteTrajectory iteration benchmarks.
Cache expensive begin and end calls in
DiscreteTrajectory iteration benchmarks.

pleroy/Principia,pleroy/Principia,pleroy/Principia,pleroy/Principia,mockingbirdnest/Principia,mockingbirdnest/Principia,mockingbirdnest/Principia,mockingbirdnest/Principia