public void Split( 
   Layer layer,
   long oid,
   SplitMethod splitMethod
)

var splitFeatures = new EditOperation() { Name = "Split Features" };

var splitPoints = new List<MapPoint>() { mp1, mp2, mp3 };

//Split the feature at 3 points
splitFeatures.Split(featureLayer, oid, splitPoints);

// split using percentage
var splitByPercentage = new SplitByPercentage() { Percentage = 33, SplitFromStartPoint = true };
splitFeatures.Split(featureLayer, oid, splitByPercentage);

// split using equal parts
var splitByEqualParts = new SplitByEqualParts() { NumParts = 3 };
splitFeatures.Split(featureLayer, oid, splitByEqualParts);

// split using single distance
var splitByDistance = new SplitByDistance() { Distance = 27.3, SplitFromStartPoint = false };
splitFeatures.Split(featureLayer, oid, splitByDistance);

// split using varying distance
var distances = new List<double>() { 12.5, 38.2, 89.99 };
var splitByVaryingDistance = new SplitByVaryingDistance() { Distances = distances, SplitFromStartPoint = true, ProportionRemainder = true };
splitFeatures.Split(featureLayer, oid, splitByVaryingDistance);

//Execute to execute the operation
//Must be called within QueuedTask.Run
if (!splitFeatures.IsEmpty)
{
  var result = splitFeatures.Execute(); //Execute and ExecuteAsync will return true if the operation was successful and false if not
}

//or use async flavor
//await splitAtPointsFeatures.ExecuteAsync();