fix: add feature flag for improved mutate rows throttling

PiperOrigin-RevId: 565090488

google/bigtable/v2/feature_flags.proto

@@ -24,24 +24,30 @@ option java_package = "com.google.bigtable.v2";
 option php_namespace = "Google\\Cloud\\Bigtable\\V2";
 option ruby_package = "Google::Cloud::Bigtable::V2";
 
-// Feature flags supported by a client.
+// Feature flags supported or enabled by a client.
 // This is intended to be sent as part of request metadata to assure the server
 // that certain behaviors are safe to enable. This proto is meant to be
 // serialized and websafe-base64 encoded under the `bigtable-features` metadata
 // key. The value will remain constant for the lifetime of a client and due to
 // HTTP2's HPACK compression, the request overhead will be tiny.
-// This is an internal implementation detail and should not be used by endusers
+// This is an internal implementation detail and should not be used by end users
 // directly.
 message FeatureFlags {
   // Notify the server that the client supports reverse scans. The server will
   // reject ReadRowsRequests with the reverse bit set when this is absent.
   bool reverse_scans = 1;
 
   // Notify the server that the client enables batch write flow control by
-  // requesting RateLimitInfo from MutateRowsResponse.
+  // requesting RateLimitInfo from MutateRowsResponse. Due to technical reasons,
+  // this disables partial retries.
   bool mutate_rows_rate_limit = 3;
 
+  // Notify the server that the client enables batch write flow control by
+  // requesting RateLimitInfo from MutateRowsResponse. With partial retries
+  // enabled.
+  bool mutate_rows_rate_limit2 = 5;
+
   // Notify the server that the client supports the last_scanned_row field
-  // in ReadRowsResponse for long-running sparse scans.
+  // in ReadRowsResponse for long-running scans.
   bool last_scanned_row_responses = 4;
 }