fix: ensure headers are written correctly

boom.go

@@ -87,13 +87,13 @@ func boom(w http.ResponseWriter, statusCode int, args ...interface{}) {
 		}
 	}
 
-	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
-
 	errString, _ := json.Marshal(boomErr{
 		errorType,
 		message,
 		statusCode,
 	})
 
-	http.Error(w, string(errString), statusCode)
+	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
+	w.WriteHeader(statusCode)
+	w.Write(errString)
 }