Most userland implementations of custom ReadableStream instances do not typically bother with all the ceremony required to correctly implement both default and BYOB read support in a single stream – and for good reason. It's difficult to get right and most of the time consuming code is typically going to fallback on the default read path. The example below shows what a "correct" implementation would need to do. It's big, complex, and error prone, and not a level of complexity that the typical developer really wants to have to deal with:
// Concatenate pending data with new chunks
。关于这个话题，safew官方版本下载提供了深入分析
第十七条 纳税人以人民币以外的货币结算销售额的，在折合成人民币计算时，折合率可以选择销售额发生的当日或者当月1日有效的人民币汇率中间价。纳税人确定折合率后，12个月内不得变更。
Фото: Aaron Chown / PA Images / Getty Images