pipeOutputStream.wait() on OutboundMessage not notified after filling tcp kernel buffers

I'm trying to invoke remotely an EJB method that involves a high volume data transfer between client and server.
After filling the tcp kernel buffers (org.xnio.channels.FramedMessageChannel.doFlushBuffer() returns with remaining data in transmitBuffer) the next call to org.jboss.remoting3.remote.new BufferWriter()

.accept(Pooled<ByteBuffer>, boolean) remains indefinitely at code line "pipeOutputStream.wait()".
The call lifecycle never ends and the client application freezes.
Incrementing the tcp_wmem kernel parameter the remote call succeeds.