message: refactor(chunk): remove leftover
diff: @@ -79,6 +79,12 @@ export abstract class Chunk<A> implements Iterable<A> {
  concat<A1>(that: Chunk<A1>): Chunk<A | A1> {
  concrete(this)
  concrete(that)
  + if (this._typeId === EmptyTypeId) {
  + return that
  + }
  + if (that._typeId === EmptyTypeId) {
  + return this
  + }
  if (this._typeId === AppendNTypeId) {
  const chunk = fromArray(this.buffer as A1[]).take(this.bufferUsed)
  return this.start.concat(chunk).concat(that)
  @@ -157,11 +163,6 @@ class Empty<A> extends Chunk<A> {
  const _Empty: Chunk<never> = new Empty()
  -export function isEmpty<A>(_: Chunk<A>): _ is Empty<A> {
  - concrete(_)
  - return _._typeId === EmptyTypeId
  -}
  -
  /**
  * @optimize remove
  */
  