message: copy structure.lookup.findUnitIndices results
  needed so structure.lookup.find can be safely called within
diff: @@ -21,6 +21,7 @@ import { HydrophobicAtomProvider, HydrophobicProvider } from './hydrophobic';
  import { SetUtils } from '../../../mol-util/set';
  import { MetalCoordinationProvider, MetalProvider, MetalBindingProvider } from './metal';
  import { refineInteractions } from './refine';
  +import { Result } from '../../../mol-math/geometry';
  export { Interactions }
  @@ -211,6 +212,7 @@ function findInterUnitContacts(structure: Structure, unitsFeatures: IntMap<Featu
  const lookup = structure.lookup3d;
  const imageCenter = Vec3.zero();
  + const closeUnits = Result.create()
  for (const unitA of structure.units) {
  if (!Unit.isAtomic(unitA)) continue;
  @@ -219,7 +221,7 @@ function findInterUnitContacts(structure: Structure, unitsFeatures: IntMap<Featu
  const bs = unitA.lookup3d.boundary.sphere;
  Vec3.transformMat4(imageCenter, bs.center, unitA.conformation.operator.matrix);
  - const closeUnits = lookup.findUnitIndices(imageCenter[0], imageCenter[1], imageCenter[2], bs.radius + maxDistance);
  + Result.copy(closeUnits, lookup.findUnitIndices(imageCenter[0], imageCenter[1], imageCenter[2], bs.radius + maxDistance));
  for (let i = 0; i < closeUnits.count; i++) {
  const unitB = structure.units[closeUnits.indices[i]];
  