diff --git a/okhttp/src/main/kotlin/com/connectrpc/okhttp/OkHttpStream.kt b/okhttp/src/main/kotlin/com/connectrpc/okhttp/OkHttpStream.kt
index a2dee5da..e1fbbfcf 100644
--- a/okhttp/src/main/kotlin/com/connectrpc/okhttp/OkHttpStream.kt
+++ b/okhttp/src/main/kotlin/com/connectrpc/okhttp/OkHttpStream.kt
@@ -213,6 +213,8 @@ internal class PipeDuplexRequestBody(
 
     override fun isDuplex() = true
 
+    override fun isOneShot() = true
+
     fun close() {
         try {
             bufferedSink.close()