[C++] Address race with closing an agent runner before the thread starts. Issue #844.
[C++] Address race with closing an agent runner before the thread starts. Issue #844.

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