Make the rest of the services have a similar raw/user interface structure.

service/taskqueue/interface.go

Index: service/taskqueue/interface.go
diff --git a/service/taskqueue/interface.go b/service/taskqueue/interface.go
index 980a1bccd8d4919801593fd1d236ddf9a9d901a5..7106bf29fc877fb3bc067bf0a6ca5fda321bde64 100644
--- a/service/taskqueue/interface.go
+++ b/service/taskqueue/interface.go
@@ -6,17 +6,39 @@ package taskqueue
 
 // Interface is the full interface to the Task Queue service.
 type Interface interface {
-	Add(task *Task, queueName string) (*Task, error)
+	// NewTask simply creates a new Task object with the Path field populated.
+	// The path parameter may be blank, if you want to use the default task path
+	// ("/_ah/queue/<queuename>").
+	NewTask(path string) *Task
+
+	Add(task *Task, queueName string) error
 	Delete(task *Task, queueName string) error
 
-	AddMulti(tasks []*Task, queueName string) ([]*Task, error)
+	AddMulti(tasks []*Task, queueName string) error
 	DeleteMulti(tasks []*Task, queueName string) error
 
-	Lease(maxTasks int, queueName string, leaseTime int) ([]*Task, error)
-	LeaseByTag(maxTasks int, queueName string, leaseTime int, tag string) ([]*Task, error)
-	ModifyLease(task *Task, queueName string, leaseTime int) error
+	// NOTE(riannucci): No support for pull taskqueues. We're not planning on
+	// making pull-queue clients which RUN in appengine (e.g. they'd all be
+	// external REST consumers). If someone needs this, it will need to be added
+	// here and in RawInterface. The theory is that a good lease API might look
+	// like:
+	//
+	//   func Lease(queueName, tag string, batchSize int, duration time.Time, cb func(*Task, error<-))
+	//
+	// Which blocks and calls cb for each task obtained. Lease would then do all
+	// necessary backoff negotiation with the backend. The callback could execute
+	// synchronously (stuffing an error into the chan or panicing if it fails), or
+	// asynchronously (dispatching a goroutine which will then populate the error
+	// channel if needed). If it operates asynchronously, it has the option of
+	// processing multiple work items at a time.
+	//
+	// Lease would also take care of calling ModifyLease as necessary to ensure
+	// that each call to cb would have 'duration' amount of time to work on the
+	// task, as well as releasing as many leased tasks as it can on a failure.
 
 	Purge(queueName string) error
 
-	QueueStats(queueNames []string) ([]Statistics, error)
+	Stats(queueNames ...string) ([]Statistics, error)
+
+	Raw() RawInterface
 }