AttachHeader is the blob of metadata that a client transmits when it
first dials into the shpool daemon indicating which shell it wants
to attach to.
AttachReplyHeader is the blob of metadata that the shpool service prefixes
the data stream with after an attach. In can be used to indicate a
connection error.
Chunk represents of a chunk of data in the output stream
DetachRequest represents a request to detach
from the given named sessions.
KillRequest represents a request to kill
the given named sessions.
ListReply is contains a list of active sessions to be displayed to the user.
ResizeRequest resizes the pty for a given named session.
We use an out-of-band request rather than doing this
in the input stream because we don’t want to have to
introduce a framing protocol for the input stream.
Session describes an active session.
SessionMessageRequest represents a request that
ought to be routed to the session indicated by
session_name
.