Arrow 之 getTypeBufferCount

arrow/java/vector/src/main/java/org/apache/arrow/vector/TypeLayout.java

 	  @Override
      public Integer visit(Struct type) {
        // validity buffer
        return 1;
      }

      @Override
      public Integer visit(Timestamp type) {
        return FIXED_WIDTH_BUFFER_COUNT;
      }

      @Override
      public Integer visit(org.apache.arrow.vector.types.pojo.ArrowType.List type) {
        // validity buffer + offset buffer
        return 2;
      }

	  @Override
      public Integer visit(Map type) {
        // validity buffer + offset buffer
        return 2;
      }