[VOL-4291] OfAgent changes for gRPC migration

Change-Id: I8da1db6df49d478ef24ec8f9bd719e9692f48a7f
diff --git a/vendor/github.com/google/uuid/uuid.go b/vendor/github.com/google/uuid/uuid.go
index 524404c..a57207a 100644
--- a/vendor/github.com/google/uuid/uuid.go
+++ b/vendor/github.com/google/uuid/uuid.go
@@ -12,6 +12,7 @@
 	"fmt"
 	"io"
 	"strings"
+	"sync"
 )
 
 // A UUID is a 128 bit (16 byte) Universal Unique IDentifier as defined in RFC
@@ -33,7 +34,27 @@
 	Future                    // Reserved for future definition.
 )
 
-var rander = rand.Reader // random function
+const randPoolSize = 16 * 16
+
+var (
+	rander      = rand.Reader // random function
+	poolEnabled = false
+	poolMu      sync.Mutex
+	poolPos     = randPoolSize     // protected with poolMu
+	pool        [randPoolSize]byte // protected with poolMu
+)
+
+type invalidLengthError struct{ len int }
+
+func (err invalidLengthError) Error() string {
+	return fmt.Sprintf("invalid UUID length: %d", err.len)
+}
+
+// IsInvalidLengthError is matcher function for custom error invalidLengthError
+func IsInvalidLengthError(err error) bool {
+	_, ok := err.(invalidLengthError)
+	return ok
+}
 
 // Parse decodes s into a UUID or returns an error.  Both the standard UUID
 // forms of xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx and
@@ -68,7 +89,7 @@
 		}
 		return uuid, nil
 	default:
-		return uuid, fmt.Errorf("invalid UUID length: %d", len(s))
+		return uuid, invalidLengthError{len(s)}
 	}
 	// s is now at least 36 bytes long
 	// it must be of the form  xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
@@ -112,7 +133,7 @@
 		}
 		return uuid, nil
 	default:
-		return uuid, fmt.Errorf("invalid UUID length: %d", len(b))
+		return uuid, invalidLengthError{len(b)}
 	}
 	// s is now at least 36 bytes long
 	// it must be of the form  xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
@@ -243,3 +264,31 @@
 	}
 	rander = r
 }
+
+// EnableRandPool enables internal randomness pool used for Random
+// (Version 4) UUID generation. The pool contains random bytes read from
+// the random number generator on demand in batches. Enabling the pool
+// may improve the UUID generation throughput significantly.
+//
+// Since the pool is stored on the Go heap, this feature may be a bad fit
+// for security sensitive applications.
+//
+// Both EnableRandPool and DisableRandPool are not thread-safe and should
+// only be called when there is no possibility that New or any other
+// UUID Version 4 generation function will be called concurrently.
+func EnableRandPool() {
+	poolEnabled = true
+}
+
+// DisableRandPool disables the randomness pool if it was previously
+// enabled with EnableRandPool.
+//
+// Both EnableRandPool and DisableRandPool are not thread-safe and should
+// only be called when there is no possibility that New or any other
+// UUID Version 4 generation function will be called concurrently.
+func DisableRandPool() {
+	poolEnabled = false
+	defer poolMu.Unlock()
+	poolMu.Lock()
+	poolPos = randPoolSize
+}