As per subject. Since https://github.com/baranowb/jboss-remoting/commit/8fa1272bcecfb4a0ac0885c3a88e3f4061bcfb4a RemoteConnectionProvider has 'private final int defaultBufferSize;' field. It is initialized in constructor as follows:

defaultBufferSize = optionMap.get(RemotingOptions.RECEIVE_BUFFER_SIZE, RemotingOptions.DEFAULT_RECEIVE_BUFFER_SIZE);

There are few pitfalls with this approach:
1. (?)There is no contract between constructor, accept and connect operations/methods. Hence confusion - what can be passed/accepted in OptionMap to constructor, accept or connect. Since said patch, it would seem that there is no distinction.
2. RECEIVE_BUFFER_SIZE is used for connect and accept and OptionMap passed to those operations/methods is ignored( to certain degree)