https://docs.microsoft.com/zh-cn/dotnet/framework/network-programming/enabling-network-tracing
启用网络跟踪
// 在App.config 配置如下,主要是"<system.diagnostics> "这节,就会在程序目录生成network.log文件,记录所有请求

<configuration>  
  <system.diagnostics>  
    <sources>  
      <source name="System.Net" tracemode="includehex" maxdatasize="1024">  
        <listeners>  
          <add name="System.Net"/>  
        </listeners>  
      </source>  
      <source name="System.Net.Cache">  
        <listeners>  
          <add name="System.Net"/>  
        </listeners>  
      </source>  
      <source name="System.Net.Http">  
        <listeners>  
          <add name="System.Net"/>  
        </listeners>  
      </source>  
      <source name="System.Net.Sockets">  
        <listeners>  
          <add name="System.Net"/>  
        </listeners>  
      </source>  
      <source name="System.Net.WebSockets">  
        <listeners>  
          <add name="System.Net"/>  
        </listeners>  
      </source>  
    </sources>  
    <switches>  
      <add name="System.Net" value="Verbose"/>  
      <add name="System.Net.Cache" value="Verbose"/>  
      <add name="System.Net.Http" value="Verbose"/>  
      <add name="System.Net.Sockets" value="Verbose"/>  
      <add name="System.Net.WebSockets" value="Verbose"/>  
    </switches>  
    <sharedListeners>  
      <add name="System.Net"  
        type="System.Diagnostics.TextWriterTraceListener"  
        initializeData="network.log"
        traceOutputOptions="ProcessId, DateTime" 
      />  
    </sharedListeners>  
    <trace autoflush="true"/>  
  </system.diagnostics>  
</configuration>