A metafunction to return the type of the lowest layer used in a type representing a stack of stream layers. This is the type of reference returned by [link beast.ref.boost__beast__get_lowest_layer `get_lowest_layer`]
A metafunction to return the type of the lowest layer used in a type representing a stack of stream layers. This is the type of reference returned by [link beast.ref.boost__beast__get_lowest_layer `get_lowest_layer`]