TypedMetadata

The phantom base of every user metadata class, mirroring commons metadata.scala:319's TypedMetadata[T].

T is the type the metadata DESCRIBES — a method's result type or a parameter's type. It carries no field; it exists so a metadata class can declare WHAT it is metadata-for, and so the materialize macro / @composite recursion can summon nested metadata for the right T. A metadata class extends TypedMetadata[T] and has its constructor params steered by the marker annotations (@reifyName/@reifyAnnot/@infer/@composite/@rpcMethodMetadata/@rpcParamMetadata).