[c++] Simplify code by removing string stream use.
[c++] Simplify code by removing string stream use.

real-logic/Aeron,real-logic/Aeron,EvilMcJerkface/Aeron,real-logic/Aeron,mikeb01/Aeron,EvilMcJerkface/Aeron,galderz/Aeron,mikeb01/Aeron,mikeb01/Aeron,galderz/Aeron,mikeb01/Aeron,galderz/Aeron,real-logic/Aeron,EvilMcJerkface/Aeron,EvilMcJerkface/Aeron,galderz/Aeron