Constant ITER_PERFORMANCE_TIPPING_SIZE_DIFF
pub(in ::collections::btree::set) const ITER_PERFORMANCE_TIPPING_SIZE_DIFF: usize = 16usize;ITER_PERFORMANCE_TIPPING_SIZE_DIFFpub(in ::collections::btree::set) const ITER_PERFORMANCE_TIPPING_SIZE_DIFF: usize = 16usize;