code: public static MapBlock createMapBlockInternal(
              int startOffset,
              int positionCount,
              Optional<boolean[]> mapIsNull,
              int[] offsets,
              Block keyBlock,
              Block valueBlock,
              HashTables hashTables,
              Type keyType,
              MethodHandle keyBlockNativeEquals,
              MethodHandle keyNativeHashCode,
              MethodHandle keyBlockHashCode)
      {
          validateConstructorArguments(startOffset, positionCount, mapIsNull.orElse(null), offsets, keyBlock, valueBlock, keyType, keyBlockNativeEquals, keyNativeHashCode);
          requireNonNull(hashTables, "hashTables is null");
          return new MapBlock(
                  startOffset,
                  positionCount,
                  mapIsNull.orElse(null),
                  offsets,
                  keyBlock,
                  valueBlock,
                  hashTables,
                  keyType,
                  keyBlockNativeEquals,
                  keyNativeHashCode,
                  keyBlockHashCode);
      }
docs: Create a map block directly without per element validations.
  <p>
  Internal use by this package and com.facebook.presto.spi.Type only.
  
  @param keyType key type K
  @param keyBlockNativeEquals equality between key stack type and a block+position; signature is (K, Block, int)boolean
  @param keyNativeHashCode hash of a key stack type; signature is (K)long