doc/rfc: separate consistent request from range request

Documentation/rfc/v3api.proto

@@ -3,9 +3,12 @@ syntax = "proto3";
 // Interface exported by the server.
 service etcd {
   // Range gets the keys in the range from the store.
-  // Maybe rename it to GET?
   rpc Range(RangeRequest) returns (RangeResponse) {}
 
+  // ConsistentRange gets the keys in the range from the store consistently across 
+  // multiple requests. Only etcd leader can serve ConsistentRangeRequest.
+  rpc ConsistentRange(ConsistentRangeRequest) returns (ConsistentRangeResponse) {}
+
   // Put puts the given key into the store.
   // A put request increases the index of the store,
   // and generates one event in the event history.
@@ -75,24 +78,28 @@ message RangeRequest {
   optional bytes range_end = 2;
   // limit the number of keys returned.
   optional int64 limit = 3;
-  // if not all the keys are returned, a continue id will be 
-  // returned in the range response if consistent is set.
-  // the returned continue id only works with the previous 
-  // etcdserver the client connected to. 
-  optional bool consistent = 4
-  // continue the previous range request in a consistent
-  // manner if a continue id is provided.
-  optional int64 continue_id = 5;
 }
 
 message RangeResponse {
   optional ResponseHeader header = 1;
   repeated KeyValue kvs = 2;
-  optional continue_id = 3;
-  // the next range request with continue_id must
-  // be issued with in continue_timeout to the
-  // same server.
-  optional continue_timeout = 4;
+}
+
+message ConsistentRangeRequest {
+  optional RangeRequest request = 1;
+  // the result is consistent with previous request with same token if the token is 
+  // given and is vaild.
+  // if the token is not given, a consistent token will be returned in the response
+  // for future use.
+  optional int64 consistent_token = 2;
+}
+
+message ConsistentRangeResponse {
+  optional RangeResponse response = 1;
+  optional consistent_token = 2;
+  // the next range request with consistent_token must
+  // be issued with in timeout
+  optional int64 timeout = 3;
 }
 
 message PutRequest {