public static Execution onServers(RegionService regionService) {
    return getFunctionExecutionService().onServers(regionService);
  }
Returns an {@link Execution} object that can be used to execute a data independent function on
all the servers that the given cache is connected to. If one of the servers goes down while
dispatching or executing the function on the server, an Exception will be thrown.

@param regionService obtained from {@link ClientCacheFactory#create} or
       {@link ClientCache#createAuthenticatedView(Properties)}.
@return an {@link Execution} object that can be used to execute a data independent function on
        all the servers that the given cache is connected to
@throws FunctionException if cache is null, is not on a client, or it does not have a default
        pool
@since GemFire 6.5
geode-core/src/main/java/org/apache/geode/cache/execute/FunctionService.java