Scattered cache key iteration is slow

15:08:13,651 TRACE (testng-Test:[]) [InvocationContextInterceptor] Invoked with command SizeCommand{} and InvocationContext [org.infinispan.context.impl.NonTxInvocationContext@7e8d563c]
15:08:13,653 TRACE (testng-Test:[]) [JGroupsTransport] Test-NodeA sending single request 110 to Test-NodeC: PublisherRequestCommand{, includeLoader=true, topologyId=5, segments={86-127 213-255}, keys=[], excludedKeys=[], transformer= org.infinispan.reactive.publisher.PublisherReducers$SumReducer@2dbe8878, finalizer=org.infinispan.reactive.publisher.PublisherReducers$SumFinalizer@365f2f3c}
15:08:13,657 TRACE (jgroups-7,Test-NodeC:[]) [JGroupsTransport] Test-NodeC received request 110 from Test-NodeA: PublisherRequestCommand{, includeLoader=true, topologyId=5, segments={86-127 213-255}, keys=[], excludedKeys=[], transformer= org.infinispan.reactive.publisher.PublisherReducers$SumReducer@2dbe8878, finalizer=org.infinispan.reactive.publisher.PublisherReducers$SumFinalizer@365f2f3c}
15:08:13,657 TRACE (testng-Test:[]) [InvocationContextInterceptor] Invoked with command KeySetCommand{, flags=[CACHE_MODE_LOCAL, REMOTE_ITERATION, IGNORE_TRANSACTION]} and InvocationContext [org.infinispan.context.impl.NonTxInvocationContext@438a1162]
15:08:13,658 TRACE (jgroups-7,Test-NodeC:[]) [InvocationContextInterceptor] Invoked with command KeySetCommand{, flags=[CACHE_MODE_LOCAL, REMOTE_ITERATION, IGNORE_TRANSACTION]} and InvocationContext [org.infinispan.context.impl.NonTxInvocationContext@3c93a27b]
15:08:13,659 TRACE (jgroups-7,Test-NodeB:[]) [InvocationContextInterceptor] Invoked with command KeySetCommand{, flags=[CACHE_MODE_LOCAL, REMOTE_ITERATION, IGNORE_TRANSACTION]} and InvocationContext [org.infinispan.context.impl.NonTxInvocationContext@2d52a0aa]
15:08:13,694 TRACE (jgroups-7,Test-NodeC:[]) [KeyStreamSupplier] Applying segment filter {86}
15:08:14,309 TRACE (jgroups-7,Test-NodeC:[]) [KeyStreamSupplier] Applying segment filter {87}
15:08:28,493 TRACE (jgroups-7,Test-NodeC:[]) [KeyStreamSupplier] Applying segment filter {126}
15:08:28,657 TRACE (timeout-thread-Test-NodeA-p25-t1:[]) [ClusterPublisherManagerImpl] General error encountered when executing publisher request command
org.infinispan.util.concurrent.TimeoutException: ISPN000476: Timed out waiting for responses for request 110 from Test-NodeC
15:08:28,861 TRACE (jgroups-7,Test-NodeC:[]) [KeyStreamSupplier] Applying segment filter {127}
15:08:36,378 TRACE (jgroups-7,Test-NodeC:[]) [KeyStreamSupplier] Applying segment filter {253}

15:08:36,496 ERROR (testng-Test:[]) [TestSuiteProgress] Test failed: org.infinispan.globalstate.ThreeNodeScatteredGlobalStateRestartTest.testFailedRestartWithExtraneousCoordinator
org.infinispan.util.concurrent.TimeoutException: ISPN000476: Timed out waiting for responses for request 110 from Test-NodeC
	at org.infinispan.interceptors.impl.AsyncInterceptorChainImpl.invoke(AsyncInterceptorChainImpl.java:255) ~[classes/:?]
	at org.infinispan.cache.impl.InvocationHelper.doInvoke(InvocationHelper.java:297) ~[classes/:?]
	at org.infinispan.cache.impl.InvocationHelper.invoke(InvocationHelper.java:101) ~[classes/:?]
	at org.infinispan.cache.impl.CacheImpl.size(CacheImpl.java:497) ~[classes/:?]
	at org.infinispan.cache.impl.CacheImpl.size(CacheImpl.java:492) ~[classes/:?]
	at org.infinispan.cache.impl.AbstractDelegatingCache.size(AbstractDelegatingCache.java:369) ~[classes/:?]
	at org.infinispan.globalstate.AbstractGlobalStateRestartTest.checkData(AbstractGlobalStateRestartTest.java:190) ~[test-classes/:?]
	at org.infinispan.globalstate.AbstractGlobalStateRestartTest.createInitialCluster(AbstractGlobalStateRestartTest.java:208) ~[test-classes/:?]
	at org.infinispan.globalstate.AbstractGlobalStateRestartTest.shutdownAndRestart(AbstractGlobalStateRestartTest.java:85) ~[test-classes/:?]
	at org.infinispan.globalstate.ThreeNodeScatteredGlobalStateRestartTest.testFailedRestartWithExtraneousCoordinator(ThreeNodeScatteredGlobalStateRestartTest.java:31) ~[test-classes/:?]