public MapMaker initialCapacity(int initialCapacity){
  builder.initialCapacity(initialCapacity);
  return this;
}

public MapMaker initialCapacity ( int initialCapacity ) { builder . initialCapacity ( initialCapacity ) ; return this ; }
sets a custom initial capacity ( defaults to 16 ) . resizing this or any other kind of hash table is a relatively slow operation , so , when possible , it is a good idea to provide estimates of expected table sizes .
