diff --git a/vendor/google.golang.org/grpc/internal/grpcutil/encode_duration.go b/vendor/google.golang.org/grpc/internal/grpcutil/encode_duration.go
new file mode 100644
index 0000000..b25b0ba
--- /dev/null
+++ b/vendor/google.golang.org/grpc/internal/grpcutil/encode_duration.go
@@ -0,0 +1,63 @@
+/*
+ *
+ * Copyright 2020 gRPC authors.
+ *
+ * Licensed 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 grpcutil
+
+import (
+	"strconv"
+	"time"
+)
+
+const maxTimeoutValue int64 = 100000000 - 1
+
+// div does integer division and round-up the result. Note that this is
+// equivalent to (d+r-1)/r but has less chance to overflow.
+func div(d, r time.Duration) int64 {
+	if d%r > 0 {
+		return int64(d/r + 1)
+	}
+	return int64(d / r)
+}
+
+// EncodeDuration encodes the duration to the format grpc-timeout header
+// accepts.
+//
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests
+func EncodeDuration(t time.Duration) string {
+	// TODO: This is simplistic and not bandwidth efficient. Improve it.
+	if t <= 0 {
+		return "0n"
+	}
+	if d := div(t, time.Nanosecond); d <= maxTimeoutValue {
+		return strconv.FormatInt(d, 10) + "n"
+	}
+	if d := div(t, time.Microsecond); d <= maxTimeoutValue {
+		return strconv.FormatInt(d, 10) + "u"
+	}
+	if d := div(t, time.Millisecond); d <= maxTimeoutValue {
+		return strconv.FormatInt(d, 10) + "m"
+	}
+	if d := div(t, time.Second); d <= maxTimeoutValue {
+		return strconv.FormatInt(d, 10) + "S"
+	}
+	if d := div(t, time.Minute); d <= maxTimeoutValue {
+		return strconv.FormatInt(d, 10) + "M"
+	}
+	// Note that maxTimeoutValue * time.Hour > MaxInt64.
+	return strconv.FormatInt(div(t, time.Hour), 10) + "H"
+}
diff --git a/vendor/google.golang.org/grpc/internal/grpcutil/metadata.go b/vendor/google.golang.org/grpc/internal/grpcutil/metadata.go
new file mode 100644
index 0000000..6f22bd8
--- /dev/null
+++ b/vendor/google.golang.org/grpc/internal/grpcutil/metadata.go
@@ -0,0 +1,40 @@
+/*
+ *
+ * Copyright 2020 gRPC authors.
+ *
+ * Licensed 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 grpcutil
+
+import (
+	"context"
+
+	"google.golang.org/grpc/metadata"
+)
+
+type mdExtraKey struct{}
+
+// WithExtraMetadata creates a new context with incoming md attached.
+func WithExtraMetadata(ctx context.Context, md metadata.MD) context.Context {
+	return context.WithValue(ctx, mdExtraKey{}, md)
+}
+
+// ExtraMetadata returns the incoming metadata in ctx if it exists.  The
+// returned MD should not be modified. Writing to it may cause races.
+// Modification should be made to copies of the returned MD.
+func ExtraMetadata(ctx context.Context) (md metadata.MD, ok bool) {
+	md, ok = ctx.Value(mdExtraKey{}).(metadata.MD)
+	return
+}
diff --git a/vendor/google.golang.org/grpc/internal/grpcutil/method.go b/vendor/google.golang.org/grpc/internal/grpcutil/method.go
new file mode 100644
index 0000000..4e74750
--- /dev/null
+++ b/vendor/google.golang.org/grpc/internal/grpcutil/method.go
@@ -0,0 +1,84 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed 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 grpcutil
+
+import (
+	"errors"
+	"strings"
+)
+
+// ParseMethod splits service and method from the input. It expects format
+// "/service/method".
+//
+func ParseMethod(methodName string) (service, method string, _ error) {
+	if !strings.HasPrefix(methodName, "/") {
+		return "", "", errors.New("invalid method name: should start with /")
+	}
+	methodName = methodName[1:]
+
+	pos := strings.LastIndex(methodName, "/")
+	if pos < 0 {
+		return "", "", errors.New("invalid method name: suffix /method is missing")
+	}
+	return methodName[:pos], methodName[pos+1:], nil
+}
+
+const baseContentType = "application/grpc"
+
+// ContentSubtype returns the content-subtype for the given content-type.  The
+// given content-type must be a valid content-type that starts with
+// "application/grpc". A content-subtype will follow "application/grpc" after a
+// "+" or ";". See
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details.
+//
+// If contentType is not a valid content-type for gRPC, the boolean
+// will be false, otherwise true. If content-type == "application/grpc",
+// "application/grpc+", or "application/grpc;", the boolean will be true,
+// but no content-subtype will be returned.
+//
+// contentType is assumed to be lowercase already.
+func ContentSubtype(contentType string) (string, bool) {
+	if contentType == baseContentType {
+		return "", true
+	}
+	if !strings.HasPrefix(contentType, baseContentType) {
+		return "", false
+	}
+	// guaranteed since != baseContentType and has baseContentType prefix
+	switch contentType[len(baseContentType)] {
+	case '+', ';':
+		// this will return true for "application/grpc+" or "application/grpc;"
+		// which the previous validContentType function tested to be valid, so we
+		// just say that no content-subtype is specified in this case
+		return contentType[len(baseContentType)+1:], true
+	default:
+		return "", false
+	}
+}
+
+// ContentType builds full content type with the given sub-type.
+//
+// contentSubtype is assumed to be lowercase
+func ContentType(contentSubtype string) string {
+	if contentSubtype == "" {
+		return baseContentType
+	}
+	return baseContentType + "+" + contentSubtype
+}
diff --git a/vendor/google.golang.org/grpc/internal/grpcutil/target.go b/vendor/google.golang.org/grpc/internal/grpcutil/target.go
new file mode 100644
index 0000000..8833021
--- /dev/null
+++ b/vendor/google.golang.org/grpc/internal/grpcutil/target.go
@@ -0,0 +1,89 @@
+/*
+ *
+ * Copyright 2020 gRPC authors.
+ *
+ * Licensed 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 grpcutil provides a bunch of utility functions to be used across the
+// gRPC codebase.
+package grpcutil
+
+import (
+	"strings"
+
+	"google.golang.org/grpc/resolver"
+)
+
+// split2 returns the values from strings.SplitN(s, sep, 2).
+// If sep is not found, it returns ("", "", false) instead.
+func split2(s, sep string) (string, string, bool) {
+	spl := strings.SplitN(s, sep, 2)
+	if len(spl) < 2 {
+		return "", "", false
+	}
+	return spl[0], spl[1], true
+}
+
+// ParseTarget splits target into a resolver.Target struct containing scheme,
+// authority and endpoint. skipUnixColonParsing indicates that the parse should
+// not parse "unix:[path]" cases. This should be true in cases where a custom
+// dialer is present, to prevent a behavior change.
+//
+// If target is not a valid scheme://authority/endpoint as specified in
+// https://github.com/grpc/grpc/blob/master/doc/naming.md,
+// it returns {Endpoint: target}.
+func ParseTarget(target string, skipUnixColonParsing bool) (ret resolver.Target) {
+	var ok bool
+	if strings.HasPrefix(target, "unix-abstract:") {
+		if strings.HasPrefix(target, "unix-abstract://") {
+			// Maybe, with Authority specified, try to parse it
+			var remain string
+			ret.Scheme, remain, _ = split2(target, "://")
+			ret.Authority, ret.Endpoint, ok = split2(remain, "/")
+			if !ok {
+				// No Authority, add the "//" back
+				ret.Endpoint = "//" + remain
+			} else {
+				// Found Authority, add the "/" back
+				ret.Endpoint = "/" + ret.Endpoint
+			}
+		} else {
+			// Without Authority specified, split target on ":"
+			ret.Scheme, ret.Endpoint, _ = split2(target, ":")
+		}
+		return ret
+	}
+	ret.Scheme, ret.Endpoint, ok = split2(target, "://")
+	if !ok {
+		if strings.HasPrefix(target, "unix:") && !skipUnixColonParsing {
+			// Handle the "unix:[local/path]" and "unix:[/absolute/path]" cases,
+			// because splitting on :// only handles the
+			// "unix://[/absolute/path]" case. Only handle if the dialer is nil,
+			// to avoid a behavior change with custom dialers.
+			return resolver.Target{Scheme: "unix", Endpoint: target[len("unix:"):]}
+		}
+		return resolver.Target{Endpoint: target}
+	}
+	ret.Authority, ret.Endpoint, ok = split2(ret.Endpoint, "/")
+	if !ok {
+		return resolver.Target{Endpoint: target}
+	}
+	if ret.Scheme == "unix" {
+		// Add the "/" back in the unix case, so the unix resolver receives the
+		// actual endpoint in the "unix://[/absolute/path]" case.
+		ret.Endpoint = "/" + ret.Endpoint
+	}
+	return ret
+}