[VOL-4291] OfAgent changes for gRPC migration

Change-Id: I8da1db6df49d478ef24ec8f9bd719e9692f48a7f
diff --git a/vendor/github.com/uber/jaeger-client-go/thrift/logger.go b/vendor/github.com/uber/jaeger-client-go/thrift/logger.go
new file mode 100644
index 0000000..50d44ec
--- /dev/null
+++ b/vendor/github.com/uber/jaeger-client-go/thrift/logger.go
@@ -0,0 +1,59 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package thrift
+
+import (
+	"log"
+	"os"
+)
+
+// Logger is a simple wrapper of a logging function.
+//
+// In reality the users might actually use different logging libraries, and they
+// are not always compatible with each other.
+//
+// Logger is meant to be a simple common ground that it's easy to wrap whatever
+// logging library they use into.
+//
+// See https://issues.apache.org/jira/browse/THRIFT-4985 for the design
+// discussion behind it.
+type Logger func(msg string)
+
+// NopLogger is a Logger implementation that does nothing.
+func NopLogger(msg string) {}
+
+// StdLogger wraps stdlib log package into a Logger.
+//
+// If logger passed in is nil, it will fallback to use stderr and default flags.
+func StdLogger(logger *log.Logger) Logger {
+	if logger == nil {
+		logger = log.New(os.Stderr, "", log.LstdFlags)
+	}
+	return func(msg string) {
+		logger.Print(msg)
+	}
+}
+
+func fallbackLogger(logger Logger) Logger {
+	if logger == nil {
+		return StdLogger(nil)
+	}
+	return logger
+}