Width computation semantics

[alambert-lanl]

This is related to #10

Currently, widths of all runtime dependent members are stored in OnceCells. However, this is overkill as most of these values are loaded during construction, save for self referential members.

My current proposed solution is the following

Definitions

If a member is a reader type or an optional reader, we simply store the reader/Optional. If a member is self referential, we don't store it.

get_{}_width

The current implementation shall be split into a private function that computes the width (by reading data from the buffer), called load_{dep}_width() and a public facing function called get_{dep}_width() which simply returns the width precomputed by load_{dep}_width or reader.get_width()

Constructor

Thus, the constructor shall look like

new(buf: &[u8]) -> Result<Self> {
    let mut me = Self {0};
    for dep in deps.in_order() {
        me.load_{dep}_width();
    }

   me.validate()
}

[alambert-lanl]

dropped in favor of deserializing variable width members before object creation