A crate that allows iterating over over struct's fields, getting their name and a mutable/shared reference to them.
Printing the values of all field whose name starts with "a" and are strings: ```rust use fields_iter::{FieldsInspect, FieldsIter};
fn printstartswitha(v: &dyn FieldsInspect) {
for (name, value) in FieldsIter::new(v) {
if !name.startswith('a') { continue };
let Some(value) = value.downcast_ref::
Adding one to the field add_here:
```rust
use fields_iter::{FieldsInspect, FieldsIterMut};
let v: &mut dyn FieldsInspect;
let field = FieldsIterMut::new(v)
.find(|&(name, )| name == "addhere")
.expect("no add_here field")
.1
.downcast_mut::add_here is not of type i32");
*field += 1;
```