Client.pm

    my %options = (
      SSL_startHandshake => 0,
      SSL_error_trap     => sub {
        $self->_cleanup;
        close delete $self->{handle};
        $self->emit_safe(error => $_[1]);
      },
      SSL_cert_file   => $args->{tls_cert},
      SSL_key_file    => $args->{tls_key},
      SSL_ca_file     => $args->{tls_ca}
        && -T $args->{tls_ca} ? $args->{tls_ca} : undef,
      SSL_verify_mode => $args->{tls_ca} ? 0x01 : 0x00,
      SSL_verify_callback => sub {
        warn "\033[34m$_\033[37m: " . shift
          for 'openssl opinion',
              'c-style memory address',
              'certification attributes',
              'errors',
              'c-style memory address of peer\'s own certificate';
      },
      Timeout         => $timeout
    );