diff --git a/utils/connfix/connfix.go b/utils/connfix/connfix.go
new file mode 100644
index 00000000..6c213876
--- /dev/null
+++ b/utils/connfix/connfix.go
@@ -0,0 +1,141 @@
+// Copyright 2022-2024 Sauce Labs Inc., all rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package connfix
+
+import (
+	"io"
+	"net"
+)
+
+type (
+	readFromMixin   struct{ net.Conn }
+	writeToMixin    struct{ net.Conn }
+	closeWriteMixin struct{ net.Conn }
+)
+
+func (rf readFromMixin) ReadFrom(r io.Reader) (int64, error) {
+	return rf.Conn.(io.ReaderFrom).ReadFrom(r) //nolint:forcetypeassert // we know the type is correct
+}
+
+var _ io.ReaderFrom = readFromMixin{}
+
+func (wt writeToMixin) WriteTo(w io.Writer) (int64, error) {
+	return wt.Conn.(io.WriterTo).WriteTo(w) //nolint:forcetypeassert // we know the type is correct
+}
+
+var _ io.WriterTo = writeToMixin{}
+
+type _closeWriter interface {
+	CloseWrite() error
+}
+
+func (cw closeWriteMixin) CloseWrite() error {
+	return cw.Conn.(_closeWriter).CloseWrite() //nolint:forcetypeassert // we know the type is correct
+}
+
+var _ _closeWriter = closeWriteMixin{}
+
+const (
+	readerFrom = 1 << iota
+	writerTo
+	closeWriter
+)
+
+func flags(conn net.Conn) uint8 {
+	var f uint8
+	if _, ok := conn.(io.ReaderFrom); ok {
+		f |= readerFrom
+	}
+	if _, ok := conn.(io.WriterTo); ok {
+		f |= writerTo
+	}
+	if _, ok := conn.(_closeWriter); ok {
+		f |= closeWriter
+	}
+	return f
+}
+
+// Combine returns a net.Conn that combines the functionality of the outer and inner net.Conn.
+// It detects if the inner net.Conn provides any of the following functions:
+//   - ReadFrom(r io.Reader) (int64, error)
+//   - WriteTo(w io.Writer) (int64, error) {
+//   - CloseWrite()
+//
+// and returns a net.Conn that implements the same interfaces.
+//
+// The outer net.Conn may also provide these functions,
+// they are used only if the inner net.Conn also provides them.
+// This allows the implementors of the outer net.Conn to provide implementations that are used when possible.
+func Combine(outer, inner net.Conn) net.Conn {
+	readFromMixin := func() readFromMixin {
+		if _, ok := outer.(io.ReaderFrom); ok {
+			return readFromMixin{outer}
+		}
+		return readFromMixin{inner}
+	}
+	writeToMixin := func() writeToMixin {
+		if _, ok := outer.(io.WriterTo); ok {
+			return writeToMixin{outer}
+		}
+		return writeToMixin{inner}
+	}
+	closeWriteMixin := func() closeWriteMixin {
+		if _, ok := outer.(_closeWriter); ok {
+			return closeWriteMixin{outer}
+		}
+		return closeWriteMixin{inner}
+	}
+
+	switch flags(inner) {
+	case 0:
+		return struct {
+			net.Conn
+		}{outer}
+	case readerFrom:
+		return struct {
+			net.Conn
+			io.ReaderFrom
+		}{outer, readFromMixin()}
+	case writerTo:
+		return struct {
+			net.Conn
+			io.WriterTo
+		}{outer, writeToMixin()}
+	case closeWriter:
+		return struct {
+			net.Conn
+			_closeWriter
+		}{outer, closeWriteMixin()}
+	case readerFrom | writerTo:
+		return struct {
+			net.Conn
+			io.ReaderFrom
+			io.WriterTo
+		}{outer, readFromMixin(), writeToMixin()}
+	case readerFrom | closeWriter:
+		return struct {
+			net.Conn
+			io.ReaderFrom
+			_closeWriter
+		}{outer, readFromMixin(), closeWriteMixin()}
+	case writerTo | closeWriter:
+		return struct {
+			net.Conn
+			io.WriterTo
+			_closeWriter
+		}{outer, writeToMixin(), closeWriteMixin()}
+	case readerFrom | writerTo | closeWriter:
+		return struct {
+			net.Conn
+			io.ReaderFrom
+			io.WriterTo
+			_closeWriter
+		}{outer, readFromMixin(), writeToMixin(), closeWriteMixin()}
+	default:
+		panic("unreachable")
+	}
+}
diff --git a/utils/connfix/connfix_test.go b/utils/connfix/connfix_test.go
new file mode 100644
index 00000000..21e13172
--- /dev/null
+++ b/utils/connfix/connfix_test.go
@@ -0,0 +1,67 @@
+// Copyright 2022-2024 Sauce Labs Inc., all rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package connfix
+
+import (
+	"bytes"
+	"io"
+	"net"
+	"testing"
+)
+
+type testConn struct {
+	net.Conn
+}
+
+var testAddr = &net.TCPAddr{}
+
+func (tc testConn) RemoteAddr() net.Addr {
+	return testAddr
+}
+
+func (tc testConn) WriteTo(w io.Writer) (int64, error) {
+	n, err := w.Write([]byte("test"))
+	return int64(n), err
+}
+
+func TestCombineTCPConn(t *testing.T) {
+	tconn := new(net.TCPConn)
+	if flags(tconn) == 0 {
+		t.Fatal("flags(tconn) == 0")
+	}
+
+	t.Run("basic", func(t *testing.T) {
+		conn := Combine(testConn{tconn}, tconn)
+		if flags(conn) != flags(tconn) {
+			t.Fatal("flags(conn) != flags(tconn)")
+		}
+		if conn.RemoteAddr() != testAddr {
+			t.Fatal("conn.RemoteAddr() != testAddr")
+		}
+	})
+
+	t.Run("overwrite", func(t *testing.T) {
+		conn := Combine(testConn{tconn}, tconn)
+		if flags(conn) != flags(tconn) {
+			t.Fatal("flags(conn) != flags(tconn)")
+		}
+		var buf bytes.Buffer
+		if _, err := conn.(io.WriterTo).WriteTo(&buf); err != nil {
+			t.Fatal(err)
+		}
+		if buf.String() != "test" {
+			t.Fatal("expected 'test', got", buf.String())
+		}
+	})
+
+	t.Run("no overwrite", func(t *testing.T) {
+		conn := Combine(testConn{tconn}, nil)
+		if _, ok := conn.(io.WriterTo); ok {
+			t.Fatal("expected no io.WriterTo")
+		}
+	})
+}