seize(.trj, resource, amount = 1, continue = NULL, post.seize = NULL, reject = NULL)
seize_selected(.trj, amount = 1, id = 0, continue = NULL, post.seize = NULL, reject = NULL)
release(.trj, resource, amount = 1)
release_selected(.trj, amount = 1, id = 0)post.seize OR reject is defined) or a pair of booleans
(if post.seize AND reject are defined) to indicate whether these subtrajectories
should continue to the next activity in the main trajectory.select, set_capacity, set_queue_size,
set_capacity_selected, set_queue_size_selected.