Request logger misreports the body size

[ufukty]

Context

• Response writer wrapper misses the body size #60 has filed the original problem.
• Unfortunately the Fixes the captured response writer miscounting the body size #61 solved the problem only at accounting but left the representation unsolved.
• Currently, the receptionist request logger misreports the body size as it doesn't leverage the improvements in mentioned PR.

Problem

Reduced maintainability.