Fuzz target mode [Visual Studio 2017]: Unable to capture 'drfuzz_set_arg' value from the target application function

Visual Studio 2017 (v141)
DynamoRIO 7.0.17598-0
DrMemory 1.11.17596-1

I am trying to set argument for the fuzz_target function using drfuzz_set_arg().
Target function prototype is like - void DrMemFuzzFunc(unsigned char *buffer, size_t size);
The value of 'size' comes to be correct but 'buffer' contains NULL.

Tried with every method explained in '64-Bit Reachability '.

WORK-AROUND:
Having first argument as dummy and 'drfuzz_set_arg(ctx, 0, NULL)'
void DrMemFuzzFunc(unsigned char ***dummy**, unsigned char *buffer, size_t size);
this works!