Document relays a bit

src/syndicate/relays.nim

@@ -288,7 +288,7 @@ when defined(posix):
   import std/asyncnet
   from std/nativesockets import AF_INET, AF_UNIX, IPPROTO_TCP, SOCK_STREAM, Protocol
 
-import protocols/[gatekeeper, sturdy]
+import protocols/gatekeeper
 
 type ShutdownEntity* = ref object of Entity
 
@@ -303,6 +303,8 @@ when defined(posix):
   export Unix
 
   proc connect*(turn: var Turn; socket: AsyncSocket; step: Preserve[Ref]; bootProc: ConnectProc) =
+    ## Relay a dataspace over an open `AsyncSocket`.
+    ## *`bootProc` may be called multiple times for multiple remote gatekeepers.*
     proc socketWriter(packet: sink Packet): Future[void] =
       socket.send(cast[string](encode(packet)))
     const recvSize = 0x2000
@@ -330,7 +332,8 @@ when defined(posix):
               var (success, pr) = decode(wireBuf)
               if success:
                 dispatch(relay, pr)
-              socket.recv(recvSize).addCallback(recvCb)
+              if not socket.isClosed:
+                socket.recv(recvSize).addCallback(recvCb)
         socket.recv(recvSize).addCallback(recvCb)
         turn.facet.actor.atExit do (turn: var Turn): close(socket)
         discard publish(turn, connectionClosedRef, true)
@@ -362,6 +365,8 @@ when defined(posix):
     asyncCheck(turn, fut)
 
   proc connect*(turn: var Turn; transport: Tcp; step: Preserve[Ref]; bootProc: ConnectProc) =
+    ## Relay a dataspace over TCP.
+    ## *`bootProc` may be called multiple times for multiple remote gatekeepers.*
     let socket = newAsyncSocket(
       domain = AF_INET,
       sockType = SOCK_STREAM,
@@ -372,6 +377,8 @@ when defined(posix):
       connect(turn, socket, step, bootProc)
 
   proc connect*(turn: var Turn; transport: Unix; step: Preserve[Ref]; bootProc: ConnectProc) =
+    ## Relay a dataspace over a UNIX socket.
+    ## *`bootProc` may be called multiple times for multiple remote gatekeepers.*
     let socket = newAsyncSocket(
       domain = AF_UNIX,
       sockType = SOCK_STREAM,