A number of configuration preprocessor definitions can be used to change the behavior of Beast. The user should assume that they introduce significant changes to the public part of this library's API and make sure that all translation units (usually files) compiled and linked into a program use the same combination of configuration macros, failure to do so may result in violations of ODR (One Definition Rule).
Enables the split compilation mode, which allows the user to compile definitions of non-template entities in a single translation unit, thus improving compilation speed. That translation unit has to include boost/beast/src.hpp in order to compile the definitions.