public GrpcClientBuilder exceptionHandler(GrpcExceptionHandlerFunction exceptionHandler) {
        requireNonNull(exceptionHandler, "exceptionHandler");
        if (this.exceptionHandler == null) {
            this.exceptionHandler = exceptionHandler;
        } else {
            this.exceptionHandler = this.exceptionHandler.orElse(exceptionHandler);
        }
        return this;
    }
Sets the specified {@link GrpcExceptionHandlerFunction} that maps a {@link Throwable}
to a gRPC {@link Status}.
grpc/src/main/java/com/linecorp/armeria/client/grpc/GrpcClientBuilder.java