*/
        Map<String, Object> getData();
    }

    /**
     * Initializes the spy.
     *
     * @param context The event spy context, never {@code null}.
     */
    void init(Context context) throws Exception;

    /**
     * Notifies the spy of some build event/operation.
     *
     * @param event The event, never {@code null}.

    SpyAppendable spy = new SpyAppendable();
    Writer writer = new AppendableWriter(spy);

    writer.write("Hello");
    assertFalse(spy.flushed);
    assertFalse(spy.closed);

    writer.flush();
    assertTrue(spy.flushed);
    assertFalse(spy.closed);

    writer.close();
    assertTrue(spy.flushed);
    assertTrue(spy.closed);
  }

                logError("close", e, eventSpy);
            }
        }
    }

    private void logError(String action, Throwable e, EventSpy spy) {
        String msg = "Failed to " + action + " spy " + spy.getClass().getName() + ": " + e.getMessage();

        if (logger.isDebugEnabled()) {
            logger.warn(msg, e);
        } else {
            logger.warn(msg);
        }