C#中Socket关闭 Close、Dispose、Shutdown、Disconnect

An answer on StackOverflow made
me think I have finally reached some glimpse of an understanding. Then I went testing for a bit and here's the summary of a newbie's view. Please correct me if I'm wrong because this is based on inference, not expertise.

Shutdown

Shutdown

 disables
the 

Send

 and/or 

Receive

 methods,
depending on the provided argument. It doesn't disable the underlying protocol handling and it never blocks.

If 

Send

 is
disabled, it also queues up a zero-byte send packet into the underlying send buffer. When the other side receives this packet, it knows that your socket will no longer send any data.

If 

Receive

 is
disabled, any data the other side might be trying to send will be lost.

If 

Receive

 is
disabled without disabling 

Send

,
it just prevents the socket from receiving data. Since no zero-byte packet will be sent, the other side won't know anything about it until it tries to send something, and only if the socket's protocol requires acknowledging.

Disconnect

First, 

Disconnect

 does
the equivalent of 

Shutdown(SocketShutdown.Both)

.

Then it blocks, waiting for two things:
For all the queued-up send data to be sent.
For the other side to acknowledge the zero-byte packet (if applicable to the underlying protocol).

If you call 

Disconnect(false)

,
system resources will be freed.

Close

Close

 frees
system resources. May abruptly stop sending queued-up data. If called with the argument, will wait for the data to be sent, but only up to the specified timeout.

Dispose

Dispose

 is
same as the 

Close

 overload
without the timeout argument. To be more precise, 

Close

without
timeout is the same as 

Dispose

.

If you use the 

using

 block
on the socket, it will automatically call 

Dispose

.