ycl coro relay join

package require {ycl coro relay}
namespace import [yclprefix]::coro::relay

dict set tasks [relay call 0 cl::Buffer copy $a] 1
dict set tasks [relay call 0 cl::Buffer copy $b] 2
for {set i 0} {$i < 2} {incr i} {
	set device_buf [relay receive]
	catch {relay receive} result options
	set t [dict get tasks [dict get $options -id]]
	kernel_$t bind $device_buf
	dict set tasks2 [relay call kernel_$t execute] $t
}
for {set i 0} {$i < 2} {incr i} {
	catch {relay receive} result options
	set result_[dict get $tasks2 [dict get $options -id]] $result
}
do something with $result_1 $result_2