public static void set(RequestContext ctx, CallOptions options) {
        requireNonNull(ctx, "ctx");
        requireNonNull(options, "options");
        ctx.setAttr(GRPC_CALL_OPTIONS, options);
    }
Sets the specified {@link CallOptions} to the {@link RequestContext}.
grpc/src/main/java/com/linecorp/armeria/common/grpc/GrpcCallOptions.java