1. A method of determining a wiring pattern for related buffer insertion in a circuit design, comprising: clustering sinks of the circuit design based on similarities of one or more characteristics of the sinks into one or more clusters; generating a local wiring pattern in a Steiner tree format for each cluster; generating a global wiring pattern to each of the one or more clusters in a Steiner tree format; and performing buffer insertion based on the local wiring pattern and global wiring pattern.