From 9d67f90d74bb9a10aa2cfaea84eed929f48f1dfe Mon Sep 17 00:00:00 2001
From: Charles Iliya Krempeaux <iamreiver@gmail.com>
Date: Tue, 23 Jan 2024 06:06:22 -0800
Subject: [PATCH] initial commits

---
 copyn.go | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 copyn.go

diff --git a/copyn.go b/copyn.go
new file mode 100644
index 0000000..706148f
--- /dev/null
+++ b/copyn.go
@@ -0,0 +1,21 @@
+package raft
+
+import (
+	"io"
+
+	"sourcecode.social/reiver/go-erorr"
+)
+
+// copyN is similar to io.CopyN(), except that if the number of bytes written (by io.CopyN()) is not 'n' then it returns an error.
+func copyN(writer io.Writer, reader io.Reader, n int64) error {
+
+	numWritten, err := io.CopyN(writer, reader, n)
+	if nil != err {
+		return erorr.Errorf("problem copying %d bytes from reader to writer: %w", n, err)
+	}
+	if expected, actual := n, numWritten ; expected != actual {
+		return erorr.Errorf("expected to write %d bytes but actually wrote %d bytes", expected, actual)
+	}
+
+	return nil
+}