What happens to logging events when the AsyncAppender buffer fills in non-blocking mode?

Issue

• We are using the AsyncAppender and have its blocking mode disabled:

<appender name="ASYNC" class="org.apache.log4j.AsyncAppender">
  <errorHandler class="org.jboss.logging.util.OnlyOnceErrorHandler"/>
  <param name="Threshold" value="INFO"/>
  <param name="Blocking" value="false"/> 
  <appender-ref ref="FILE"/>
</appender>

• What will then happen if a thread tries to log something while the AsyncAppender's buffer is full?