std::uint64_t len_ = 0; // size of chunk or body
std::uint64_t len0_ = 0; // content length if known
std::unique_ptr<char[]> buf_; // temp storage
std::uint64_t len_ = 0; // size of chunk or body
std::uint64_t len0_ = 0; // content length if known
std::unique_ptr<char[]> buf_; // temp storage