[C++] Integrate std::span support for flyweight API #1171

Job	Run time
C++ Clang 9 (Ubuntu 20.04)	1m 36s
C++ Clang 13 (Ubuntu 24.04)	1m 37s
C++ Clang 10 (Ubuntu 20.04)	1m 39s
C++ GCC 6 (Ubuntu 20.04)	2m 10s
C++ Clang 14 (Ubuntu 24.04)	1m 39s
C++ Xcode (macOS)	1m 2s
C++ Clang 11 (Ubuntu 20.04)	1m 59s
C++ GCC 7 (Ubuntu 20.04)	1m 46s
C++ Clang 15 (Ubuntu 24.04)	1m 47s
C++ Clang 12 (Ubuntu 20.04)	1m 58s
C++ GCC 8 (Ubuntu 20.04)	2m 1s
C++ Clang 16 (Ubuntu 24.04)	1m 24s
C++ GCC 11 (Ubuntu 24.04)	1m 39s
C++ Clang 17 (Ubuntu 24.04)	1m 46s
C++ GCC 9 (Ubuntu 20.04)	1m 40s
C++ GCC 12 (Ubuntu 24.04)	1m 29s
C++ Clang 18 (Ubuntu 24.04)	1m 39s
C++ GCC 10 (Ubuntu 20.04)	1m 39s
C++ MSVC (Windows) (windows-latest)	5m 9s
C++ GCC 13 (Ubuntu 24.04)	1m 34s
C++ GCC 14 (Ubuntu 24.04)	1m 28s
C# 8.0.x	2m 47s
Java 17 (ubuntu-24.04)	1m 46s
Java 17 (windows-latest)	4m 7s
Golang 1.22.x	2m 8s
Java 17 (macos-latest)	1m 19s
Java 21 (ubuntu-24.04)	1m 46s
Java 21 (windows-latest)	3m 11s
Rust stable	1m 12s
Java 21 (macos-latest)	1m 53s
Rust beta	1m 10s
Rust nightly	1m 3s
	1h 1m 3s

Provide feedback