fix: call write header in write if not written (#1598)

If `Write` is called and `WriteHeader` was not previously called, the
`WriteHeader` needs to be set to StatusOK.

internal/api/middleware.go

@@ -288,19 +288,28 @@ func (t *timeoutResponseWriter) Write(bytes []byte) (int, error) {
 	t.Lock()
 	defer t.Unlock()
 
+	if !t.wroteHeader {
+		t.writeHeaderLocked(http.StatusOK)
+	}
+
 	return t.buf.Write(bytes)
 }
 
 func (t *timeoutResponseWriter) WriteHeader(statusCode int) {
 	t.Lock()
 	defer t.Unlock()
 
+	t.writeHeaderLocked(statusCode)
+}
+
+func (t *timeoutResponseWriter) writeHeaderLocked(statusCode int) {
 	if t.wroteHeader {
 		// ignore multiple calls to WriteHeader
 		// once WriteHeader has been called once, a snapshot of the header map is taken
 		// and saved in snapHeader to be used in finallyWrite
 		return
 	}
+
 	t.statusCode = statusCode
 	t.wroteHeader = true
 	t.snapHeader = t.header.Clone()