perf: improve error handling (#739)

* perf: improve error handling

Signed-off-by: Giovanni Liva <[email protected]>

* add synchronized keyword

Signed-off-by: Giovanni Liva <[email protected]>

---------

Signed-off-by: Giovanni Liva <[email protected]>
Co-authored-by: Todd Baert <[email protected]>

Author: thisthat

src/main/java/dev/openfeature/sdk/exceptions/FlagNotFoundError.java

@@ -9,4 +9,9 @@
 public class FlagNotFoundError extends OpenFeatureError {
     private static final long serialVersionUID = 1L;
     @Getter private final ErrorCode errorCode = ErrorCode.FLAG_NOT_FOUND;
+
+    @Override
+    public synchronized Throwable fillInStackTrace() {
+        return this;
+    }
 }