private static RuntimeException executionThrowable(Throwable t) {
    if (t instanceof RuntimeException) {
      return (RuntimeException) t;
    } else if (t instanceof Error) {
      throw (Error) t;
    } else {
      throw new IllegalStateException("Don't know", t);
    }
  }
execute bulk op (putAll or removeAll) on multiple PR servers, returning a map of the results.
Results are either a VersionedObjectList or a BulkOpPartialResultsException

@return the per-server results
geode-core/src/main/java/org/apache/geode/cache/client/internal/SingleHopClientExecutor.java