# Prepend the headers if they have not yet been sent
if ( $self->_has_header_buf ) {
- $buffer = $self->_clear_header_buf . $buffer;
+ my $headers = $self->_clear_header_buf;
+
+ $buffer = defined $buffer
+ ? $headers . $buffer : $headers;
}
return $self->$orig( $c, $buffer );