diff --git a/doc/api/http.md b/doc/api/http.md
index dad22731317057..2e60fe8bcef135 100644
--- a/doc/api/http.md
+++ b/doc/api/http.md
@@ -738,7 +738,7 @@ The `encoding` argument is optional and only applies when `chunk` is a string.
 Defaults to `'utf8'`.
 
 The `callback` argument is optional and will be called when this chunk of data
-is flushed.
+is flushed, but only if the chunk is non-empty.
 
 Returns `true` if the entire data was flushed successfully to the kernel
 buffer. Returns `false` if all or part of the data was queued in user memory.