From 8e68e2b26e53c5b773c18abd33214b48e83d4247 Mon Sep 17 00:00:00 2001
From: Runxi Yu
Date: Thu, 2 Apr 2026 07:15:59 +0000
Subject: common/iowrap: Add

---
 common/iowrap/doc.go               |  2 ++
 common/iowrap/write_flusher.go     |  9 +++++++++
 common/iowrap/write_flusher_nop.go | 21 +++++++++++++++++++++
 3 files changed, 32 insertions(+)
 create mode 100644 common/iowrap/doc.go
 create mode 100644 common/iowrap/write_flusher.go
 create mode 100644 common/iowrap/write_flusher_nop.go

diff --git a/common/iowrap/doc.go b/common/iowrap/doc.go
new file mode 100644
index 00000000..8e25db16
--- /dev/null
+++ b/common/iowrap/doc.go
@@ -0,0 +1,2 @@
+// Package iowrap provides small public I/O wrapper interfaces and adapters.
+package iowrap
diff --git a/common/iowrap/write_flusher.go b/common/iowrap/write_flusher.go
new file mode 100644
index 00000000..aaac8724
--- /dev/null
+++ b/common/iowrap/write_flusher.go
@@ -0,0 +1,9 @@
+package iowrap
+
+import "io"
+
+// WriteFlusher writes bytes and flushes buffered output state.
+type WriteFlusher interface {
+	io.Writer
+	Flush() error
+}
diff --git a/common/iowrap/write_flusher_nop.go b/common/iowrap/write_flusher_nop.go
new file mode 100644
index 00000000..91d30c3e
--- /dev/null
+++ b/common/iowrap/write_flusher_nop.go
@@ -0,0 +1,21 @@
+package iowrap
+
+import "io"
+
+type nopFlusher struct {
+	io.Writer
+}
+
+// NopFlush adapts writer into a [WriteFlusher] with a no-op Flush.
+func NopFlush(writer io.Writer) WriteFlusher {
+	if writer == nil {
+		return nil
+	}
+
+	return nopFlusher{Writer: writer}
+}
+
+// Flush lets us satisfy [WriteFlusher] but does nothing.
+func (nopFlusher) Flush() error {
+	return nil
+}
-- 
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