[VOL-4291] Rw-core updates for gRPC migration

Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/go.uber.org/zap/zapcore/clock.go b/vendor/go.uber.org/zap/zapcore/clock.go
new file mode 100644
index 0000000..d2ea95b
--- /dev/null
+++ b/vendor/go.uber.org/zap/zapcore/clock.go
@@ -0,0 +1,50 @@
+// Copyright (c) 2021 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package zapcore
+
+import (
+	"time"
+)
+
+// DefaultClock is the default clock used by Zap in operations that require
+// time. This clock uses the system clock for all operations.
+var DefaultClock = systemClock{}
+
+// Clock is a source of time for logged entries.
+type Clock interface {
+	// Now returns the current local time.
+	Now() time.Time
+
+	// NewTicker returns *time.Ticker that holds a channel
+	// that delivers "ticks" of a clock.
+	NewTicker(time.Duration) *time.Ticker
+}
+
+// systemClock implements default Clock that uses system time.
+type systemClock struct{}
+
+func (systemClock) Now() time.Time {
+	return time.Now()
+}
+
+func (systemClock) NewTicker(duration time.Duration) *time.Ticker {
+	return time.NewTicker(duration)
+}