NetworkStream.Read synchorization

[Hai Ly Hoang \(MT00KSTN\)]

Hi,
FileStream.Read(buf, offset, siz) will return when reaching the end of file
or a block (size siz) can be read from the file. In the case of
NetworkStream, it's more confusing. Now, consider this case:

The server send a block of 15 letter A. At the time NetworkStream.Read is
called (on client machine), the client machine has only received 3 letter A:

Server (send): AAAAAAAAAAAAAAA
Client (receive): AAA
^___ Read(buf, 0, 50) methods is called.

Do Read method will delay until 15 letter A are received and return a block
of 15 letter or Read methods just return a block of 3 letter A (ie. return
what data the client has received) ?
If Read methods returns 3 letter A, how do we determine whether the server
has send all of its data ?

Thanks