use threads;
use threads::shared qw[ shared_clone ];

my @sessionData = ...;

my @ssh2_handles :shared;

sub opener {
    my( $idx, ... ) = @_;
    use Net::SSH2;
    
    my $ssh = Net::SSH2->new( .. );
    lock @ssh2_handles;
    $ssh2_handles[ $idx ] = shared_clone( $ssh );
    return;
}

my $idx = 0;
my @openers = async( \&opener, $idx++, $_ ) for @sessionData;

$_->join for @openers;

### use @ssh2_handles here...