MaximumFileSize设置为1 MB，log4.net仍然将10 MB写入日志文件？

Question

我已将文件大小指定为最大1 MB但在1个文件中最多写入9696 KB：

<?xml version="1.0"?>
<configuration>
    <configSections>
        <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
    </configSections>

    <log4net debug="true">
        <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
            <file value="C:\\Temp\\TestLog.txt"/>
            <appendToFile value="true"/>
            <rollingStyle value="Size"/>
            <maxSizeRollBackups value="2"/>
            <maximumFileSize value="1MB"/>
            <staticLogFileName value="true"/>
            <layout type="log4net.Layout.PatternLayout">
                <conversionPattern value="%-5p %d %5rms %-22.22c{1} %-18.18M - %m%n"/>
            </layout>
        </appender>

        <root>
            <level value="DEBUG"/>
            <appender-ref ref="RollingLogFileAppender"/>
        </root>
    </log4net>
    <startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/></startup>        
</configuration>