Function emit_service_interface 

pub fn emit_service_interface(svc: &ServiceDef) -> String

Emittiert das Service-Interface (abstrakte Klasse + HandlerInterface).

Output (vereinfacht):

namespace dds { namespace rpc {
  class Calculator {
  public:
    virtual ~Calculator() = default;
    virtual int32_t add(int32_t a, int32_t b) = 0;
    virtual ::dds::rpc::Future<int32_t> add_async(int32_t a, int32_t b) = 0;
  };
  class CalculatorHandlerInterface {
  public:
    virtual ~CalculatorHandlerInterface() = default;
    virtual int32_t add(int32_t a, int32_t b) = 0;
  };
} }