code: func (bb *Builder) SetSymlinkTarget(target string) *Builder {
  	bb.SetType("symlink")
  	if utf8.ValidString(target) {
  		bb.m["symlinkTarget"] = target
  	} else {
  		bb.m["symlinkTargetBytes"] = mixedArrayFromString(target)
  	}
  	return bb
  }
docs: // SetSymlinkTarget sets bb to be of type "symlink" and sets the symlink's target.