Function apply_measurement 

pub fn apply_measurement(
    builder: &mut FixBuilder,
    measurement: Measurement,
) -> bool

Feeds one measurement to a fix under construction.

Returns whether it was a position – the one reading that makes a fix fresh rather than merely updated, the same distinction [fix::FixBuilder::set_position] documents. Everything else this does not recognise as own-ship state (depth, the sounder’s own geometry, the vessel’s draft) is read elsewhere; this only ever touches the four fields a moving fix is made of.