public Map<ShapeId, Trait> supportedProtocols() {
        return ServiceIndex.of(model()).getProtocols(service());
    }
Get a map of supported protocols on the service shape in the form of shape ID to
the definition of the trait.

@return Returns the protocol shape IDs of the service.
@see ServiceIndex
smithy-codegen-core/src/main/java/software/amazon/smithy/codegen/core/directed/CreateContextDirective.java