Bundlers: reuse send buffer when transport == sync. --------------------------------------------------- Key: JGRP-1989 URL: https://issues.jboss.org/browse/JGRP-1989 Project: JGroups Issue Type: Enhancement Reporter: Bela Ban Assignee: Bela Ban Fix For: 3.6.7 With the addition of {{TCP_NIO2}}, all bundlers now create new send buffers for every message (or message list). This generates a lot of memory allocations, perhaps it is better to revert this change for *synchronous transports* such as {{UDP}} and {{TCP}}, and still create new buffers for *asynchronous transports* such as {{TCP_NIO2}}. Synchronous transports guarantee a message has been put on the wire when {{TP.send()}} returns, whereas asynchronous transports may only have completed a partial write (so we cannot reuse the buffer). The code in the bundler should check for this, and copy if async or not copy if sync. Whether or not a transport is sync is determined by a new abstract method that needs to be overridden by every transport.