Constant RIGHTS_POLL_FD_READWRITE 

pub const RIGHTS_POLL_FD_READWRITE: Rights = _ /* 134_217_728u64 */;

If rights::fd_read is set, includes the right to invoke poll_oneoff to subscribe to eventtype::fd_read. If rights::fd_write is set, includes the right to invoke poll_oneoff to subscribe to eventtype::fd_write.