clean up producer

server/proto/core.proto

@@ -10,7 +10,7 @@ enum TelemetryDataType {
 message TelemetryValue {
     oneof value {
         float float_32 = 1;
-        float float_64 = 2;
+        double float_64 = 2;
     }
 }
 
@@ -20,8 +20,8 @@ message UUID {
 
 // UTC since UNIX
 message Timestamp {
-    fixed64 secs = 1;
-    fixed32 nanos = 2;
+    sfixed64 secs = 1;
+    sfixed32 nanos = 2;
 }
 
 message TelemetryDefinitionRequest {