fix: update comments

Signed-off-by: Junjie Gao <[email protected]>

internal/io/limitWriter_test.go

@@ -1,3 +1,16 @@
+// Copyright The Notary Project 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 io
 
 import (

internal/io/limitwriter.go

@@ -11,6 +11,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package io provides a LimitWriter that writes to an underlying writer up to
+// a limit.
+
 package io
 
 import "io"
@@ -31,6 +34,7 @@ func NewLimitWriter(w io.Writer, limit int64) *LimitWriter {
 	return &LimitWriter{w: w, limit: limit}
 }
 
+// Write writes p to the underlying writer up to the limit.
 func (lw *LimitWriter) Write(p []byte) (int, error) {
 	remaining := lw.limit - lw.written
 	if remaining <= 0 {