Function write_bio_to_string

include/jwt-cpp/jwt.h:514–522

		template<typename error_category = error::rsa_error>
		std::string write_bio_to_string(std::unique_ptr<BIO, decltype(&BIO_free_all)>& bio_out, std::error_code& ec) {
			char* ptr = nullptr;
			auto len = BIO_get_mem_data(bio_out.get(), &ptr);
			if (len <= 0 || ptr == nullptr) {
				ec = error_category::convert_to_pem_failed;
				return {};
			}
			return {ptr, static_cast<size_t>(len)};
		}

		inline std::unique_ptr<EVP_MD_CTX, void (*)(EVP_MD_CTX*)> make_evp_md_ctx() {
			return