pub fn set(source: Source, attrs: Attrs)Expand description
Insert or replace a configuration layer for the given source.
If a layer with the same Source already exists, its
contents are replaced with the provided attrs. Otherwise a
new layer is added. After insertion, layers are re-sorted so
that higher-priority sources (e.g. Source::TestOverride,
Source::Runtime) appear before lower-priority ones
(Source::Env, Source::File).
This function is used by initialization routines (e.g.
init_from_env, init_from_yaml) and by tests when
overriding configuration values.