string
The channel style, one of the following:
"" - Channel is not open, i.e. free, unused.
"file" - Channel is open for file I/O.
"process" - Channel is open for external process I/O.
"server" - Channel is open for I/O to a data transfer server process.
"socket" - Channel is open for I/O to a communications socket.
This element cannot be changed by the user.