A MirrorSystem is the main interface used to reflect on a set of associated libraries.
At runtime each running isolate has a distinct MirrorSystem.
It is also possible to have a MirrorSystem which represents a set of libraries which are not running -- perhaps at compile-time. In this case, all available reflective functionality would be supported, but runtime functionality (such as invoking a function or inspecting the contents of a variable) would fail dynamically.
dynamic
type.
void
type.
libraryName
if it exists. [...]