feat: add error reason to RPCError in callRequest method

src/core/RPCSession.ts

@@ -242,6 +242,7 @@ export class RPCSession {
 
                 reject(new RPCError({
                     errorCode: RPCErrorCode.UNKNOWN_ERROR,
+                    reason: e instanceof Error ? e.message : `${e}`
                 }))
             })
         }