public class Poll
A Poll keeps track of file descriptors much like fd_set (used with
select) or a struct pollfd array
Once created with Poll, the set can be used to wait for file
descriptors to be readable and/or writable. It is possible to make this wait be controlled by specifying
true for the
controllable flag when creating the set (or later calling
New file descriptors are added to the set using add_fd, and removed using
remove_fd. Controlling which file descriptors should be waited for to become
readable and/or writable are done using fd_ctl_read,
Use wait to wait for the file descriptors to actually become readable and/or writable, or to timeout if no file descriptor is available in time. The wait can be controlled by calling restart and set_flushing.
Once the file descriptor set has been waited for, one can use fd_has_closed to see if the file descriptor has been closed, fd_has_error to see if it has generated an error, fd_can_read to see if it is possible to read from the file descriptor, and fd_can_write to see if it is possible to write to it.