code: func (bb *Builder) PopulateDirectoryMap(staticSetRef blob.Ref) *Builder {
  	bb.m["camliType"] = "directory"
  	bb.m["entries"] = staticSetRef.String()
  	return bb
  }
docs: // PopulateDirectoryMap sets the type of *Builder to "directory" and sets
  // the "entries" field to the provided staticSet blobref.