Move Sender interface to network pkg

@perfmode sender is exactly what we need to pass in to dht/bitswap.

bitswap/transmission/service_wrapper.go

@@ -4,11 +4,13 @@ import (
 	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
 
 	bsmsg "github.com/jbenet/go-ipfs/bitswap/message"
+	inet "github.com/jbenet/go-ipfs/net"
 	netmsg "github.com/jbenet/go-ipfs/net/message"
 	netservice "github.com/jbenet/go-ipfs/net/service"
 	peer "github.com/jbenet/go-ipfs/peer"
 )
 
+// NewServiceWrapper handles protobuf marshalling
 func NewServiceWrapper(ctx context.Context, r Receiver) Sender {
 	h := &handlerWrapper{r}
 	s := netservice.NewService(h)
@@ -49,7 +51,7 @@ func (wrapper *handlerWrapper) HandleMessage(
 }
 
 type senderWrapper struct {
-	serviceDelegate netservice.Sender
+	serviceDelegate inet.Sender
 }
 
 func (wrapper *senderWrapper) SendMessage(

net/interface.go

@@ -4,6 +4,8 @@ import (
 	msg "github.com/jbenet/go-ipfs/net/message"
 	mux "github.com/jbenet/go-ipfs/net/mux"
 	peer "github.com/jbenet/go-ipfs/peer"
+
+	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
 )
 
 // Network is the interface IPFS uses for connecting to the world.
@@ -31,3 +33,13 @@ type Network interface {
 	// Close terminates all network operation
 	Close() error
 }
+
+// Sender interface for network services.
+type Sender interface {
+	// SendMessage sends out a given message, without expecting a response.
+	SendMessage(ctx context.Context, m msg.NetMessage) error
+
+	// SendRequest sends out a given message, and awaits a response.
+	// Set Deadlines or cancellations in the context.Context you pass in.
+	SendRequest(ctx context.Context, m msg.NetMessage) (msg.NetMessage, error)
+}

net/service/interface.go

-package service
-
-import (
-	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
-	msg "github.com/jbenet/go-ipfs/net/message"
-)
-
-type Sender interface {
-	SendMessage(ctx context.Context, m msg.NetMessage, rid RequestID) error
-	SendRequest(ctx context.Context, m msg.NetMessage) (msg.NetMessage, error)
-}