8     fn set(bits: &mut Self, index: usize, value: bool) -> bool;  in set()
10     fn len(bits: &Self) -> usize;  in len()
11     fn first_index(bits: &Self) -> Option<usize>;  in first_index()
12     fn first_false_index(bits: &Self) -> Option<usize>;  in first_false_index()
13     fn last_index(bits: &Self) -> Option<usize>;  in last_index()
14     fn last_false_index(bits: &Self) -> Option<usize>;  in last_false_index()
15     fn next_index(bits: &Self, index: usize) -> Option<usize>;  in next_index()
16     fn next_false_index(bits: &Self, index: usize) -> Option<usize>;  in next_false_index()
17     fn prev_index(bits: &Self, index: usize) -> Option<usize>;  in prev_index()
18     fn prev_false_index(bits: &Self, index: usize) -> Option<usize>;  in prev_false_index()
238     fn set(&mut self, index: usize, value: bool) -> Option<bool>;  in set()
255     fn len(&self) -> usize;  in len()
257     fn size(&self) -> usize;  in size()
265     fn first_index(&self) -> Option<usize>;  in first_index()
273     fn first_false_index(&self) -> Option<usize>;  in first_false_index()
281     fn last_index(&self) -> Option<usize>;  in last_index()
289     fn last_false_index(&self) -> Option<usize>;  in last_false_index()
292     fn next_index(&self, index: usize) -> Option<usize>;  in next_index()
295     fn next_false_index(&self, index: usize) -> Option<usize>;  in next_false_index()
298     fn prev_index(&self, index: usize) -> Option<usize>;  in prev_index()
301     fn prev_false_index(&self, index: usize) -> Option<usize>;  in prev_false_index()