Set multiple pins at the same time.
The usual method of setting multiple pins
can be problematic because the time between the two operations might be significant (they are
done as two separate bus transactions). If it is desired that multiple pins change state in a
single bus transaction, the
write_multiple() function provides an interface to do this.
port_expander::write_multiple( [&mut io0, &mut io1], [true, false], ).unwrap();