Post Segment Transform Collection

Creates a new Segment Transform.

The only required field is name, but depending on how the segment transform
is created, certain fields may become required. There are two ways to create a
segment transform: directly by specifying a mapping, or by referencing other
segment transforms.

Parameter Requirements

• If creating via a mapping directly, you must also provide a
  segment_group_id
• If creating via referenced, no other fields are required.