private GrpcExceptionHandlerFunctionBuilder exceptionMappingsBuilder() {
        if (exceptionMappingsBuilder == null) {
            exceptionMappingsBuilder = GrpcExceptionHandlerFunction.builder();
        }
        return exceptionMappingsBuilder;
    }
Adds the specified exception mapping that maps a {@link Throwable} to a gRPC {@link Status}.
The mapping is used to handle a {@link Throwable} when it is raised.

<p>Note that this method and {@link #exceptionMapping(GrpcStatusFunction)}
are mutually exclusive.

@deprecated Use {@link GrpcExceptionHandlerFunctionBuilder#on(Class, GrpcExceptionHandlerFunction)}
            instead.
grpc/src/main/java/com/linecorp/armeria/server/grpc/GrpcServiceBuilder.java