UnicastLoopbackTest fails to receive all messages in the allotted time

UnicastLoopbackTest.testUnicastMessagesWithLoopback() is failing with the following error:

Error Message

Test timed out before all messages were received
Stacktrace

java.lang.AssertionError 
at org.testng.Assert.fail(Assert.java:94) 
at org.jgroups.tests.UnicastLoopbackTest.testUnicastMsgsWithLoopback(UnicastLoopbackTest.java:78) 

The test does the following:

• creates one channel with loopback enabled in the transport
• the channel is assigned a receiver which collects the messages received and sets a Boolean valued Promise when all messages have been received
• the channel sends 1000 messages to itself in a burst
• waits 20 seconds for the promise to be set to true

The test fails because the messages do not arrive within the allotted 20 seconds.