Allow the channel send and receive buffer size to be changed.

[meshlink] / src / utcp

diff --git a/src/utcp b/src/utcp
index 3bc564058072a79a22320f8c5bc50e8844896114..d394c4f4f9b820cb1866046e21b834b67fd18ecb 160000 (submodule)
--- a/src/utcp
+++ b/src/utcp
@@ -1 +1 @@
-Subproject commit 3bc564058072a79a22320f8c5bc50e8844896114
+Subproject commit d394c4f4f9b820cb1866046e21b834b67fd18ecb