Improve error generation for USDPL

nrpc/src/service.rs

@@ -54,6 +54,30 @@ pub enum ServiceError {
     }
 }
 
+impl ServiceError {
+    pub fn variant_str(&self) -> &'static str {
+        match self {
+            Self::Encode(_) => "encode",
+            Self::Decode(_) => "decode",
+            Self::MethodNotFound => "method not found",
+            Self::ServiceNotFound => "service not found",
+            Self::Method(_) => "method",
+            Self::StreamLength { .. } => "stream length",
+        }
+    }
+
+    pub fn variant(&self) -> u64 {
+        match self {
+            Self::Encode(_) => 0b10,
+            Self::Decode(_) => 0b11,
+            Self::MethodNotFound => 0b100,
+            Self::ServiceNotFound => 0b101,
+            Self::Method(_) => 0b1000,
+            Self::StreamLength { .. } => 0b10000,
+        }
+    }
+}
+
 impl std::fmt::Display for ServiceError {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {