+sub send_exec_cmd { # tell script/lei to execute a command
+ my ($self, $io, $cmd, $env) = @_;
+ my $sock = $self->{sock} // die 'lei client gone';
+ my $fds = [ map { fileno($_) } @$io ];
+ $send_cmd->($sock, $fds, exec_buf($cmd, $env), MSG_EOR);
+}
+