can't upgrade heapless to 0.6.0 yet.  :(
@@ -37,7 +37,7 @@ serde_cbor = "0.11.1"
serde_json = "1.0.62"
time = "0.2.25"
atomic-traits = "0.2.0"
-heapless = "0.6.0"
+heapless = "=0.5.6"
hash32 = "0.1.1"
uuid = { version = "0.8.2", features = [ "v4" ] }
once_cell = "1.5.2"
