![1721827433227.png](/data/attachments/43/43707-ce8f247cb7a0d8ea67c5ae24642d6c36.jpg)
The locus looks like the darker blue shaded area I think. The red circle is found from |z-1|<2, being a circle of radius 2 with centre (1,0). I found the other restriction from arg(iz+1) = arg(i(z-i)) = pi/2 + arg(z-i)
So -pi/4<arg(z-i)<0, which restricts the angle as shown.