Package set provides simple set data structures for uint64 and string types.
High-level API:
type Set(T {}) xxx
func (Set) Len() int
func (Set) Has(T) bool
func (Set) Set(T)
func (Set) Clear(T)
These data structures are useful for implementing required fields efficiently
or ensuring that protobuf identifiers do not conflict.
Change-Id: If846630a9034909a43121b3e0f6720275f4b7aaf
Reviewed-on: https://go-review.googlesource.com/128898
Reviewed-by: Chris Manghane <cmang@golang.org>
