ev/select

    cfunction

    (ev/select & clauses)

    Block until the first of several channel operations occur. Returns 
    a tuple of the form [:give chan] or [:take chan x], where a :give 
    tuple is the result of a write and :take tuple is the result of a 
    write. Each clause must be either a channel (for a channel take 
    operation) or a tuple [channel x] for a channel give operation. 
    Operations are tried in order, such that the first clauses will 
    take precedence over later clauses.