originalIndex property
An integer that indicates the corresponding value in the original request. Each value in the request should map to a snapped value in the response. However, if you've set interpolate=true, then it's possible that the response will contain more coordinates than the request. Interpolated values will not have an originalIndex. These values are indexed from 0, so a point with an originalIndex of 4 will be the snapped value of the 5th latitude/longitude passed to the path parameter.
Implementation
@BuiltValueField(wireName: r'originalIndex')
num? get originalIndex;