public sealed class ReconcileOptions 

public void ReconcileAndPost(Geodatabase geodatabase)
{
    // Get a reference to our version and our parent
    if (geodatabase.IsVersioningSupported())
    {
        using (VersionManager versionManager = geodatabase.GetVersionManager())
        using (Version currentVersion = versionManager.GetCurrentVersion())
        using (Version parentVersion = currentVersion.GetParent())
        {

            //// Create a ReconcileDescription object
            //At 2.x - 
            //ReconcileDescription reconcileDescription = new ReconcileDescription(parentVersion);
            //reconcileDescription.ConflictResolutionMethod = ConflictResolutionMethod.Continue; // continue if conflicts are found
            //reconcileDescription.WithPost = true;

            //// Reconcile and post
            //ReconcileResult reconcileResult = currentVersion.Reconcile(reconcileDescription);

            // ReconcileResult.HasConflicts can be checked as-needed

            // Create a ReconcileOptions object
            ReconcileOptions reconcileOptions = new ReconcileOptions(parentVersion);
            reconcileOptions.ConflictResolutionMethod = ConflictResolutionMethod.Continue; // continue if conflicts are found
            reconcileOptions.ConflictDetectionType = ConflictDetectionType.ByRow; //Default
            reconcileOptions.ConflictResolutionType = ConflictResolutionType.FavorTargetVersion;//or FavorEditVersion

            // Reconcile
            ReconcileResult reconcileResult = currentVersion.Reconcile(reconcileOptions);
            if (!reconcileResult.HasConflicts)
            {
                //No conflicts, perform the post
                PostOptions postOptions = new PostOptions(parentVersion);
                //var postOptions = new PostOptions(); for default version
                postOptions.ServiceSynchronizationType = ServiceSynchronizationType.Synchronous;//Default
                currentVersion.Post(postOptions);
            }

        }
    }
}

public void ReconcileAndPost2(Geodatabase geodatabase)
{
    // Get a reference to our version and our parent
    if (geodatabase.IsVersioningSupported())
    {
        using (VersionManager versionManager = geodatabase.GetVersionManager())
        using (Version currentVersion = versionManager.GetCurrentVersion())
        using (Version parentVersion = currentVersion.GetParent())
        {

            //// Create a ReconcileDescription object
            //At 2.x - 
            //ReconcileDescription reconcileDescription = new ReconcileDescription(parentVersion);
            //reconcileDescription.ConflictResolutionMethod = ConflictResolutionMethod.Continue; // continue if conflicts are found
            //reconcileDescription.WithPost = true;

            //// Reconcile and post
            //ReconcileResult reconcileResult = currentVersion.Reconcile(reconcileDescription);

            // ReconcileResult.HasConflicts can be checked as-needed

            // Create a ReconcileOptions object
            ReconcileOptions reconcileOptions = new ReconcileOptions(parentVersion);
            reconcileOptions.ConflictResolutionMethod = ConflictResolutionMethod.Continue; // continue if conflicts are found
            reconcileOptions.ConflictDetectionType = ConflictDetectionType.ByRow; //Default
            reconcileOptions.ConflictResolutionType = ConflictResolutionType.FavorTargetVersion;//or FavorEditVersion

            PostOptions postOptions = new PostOptions(parentVersion);
            //var postOptions = new PostOptions(); for default version
            postOptions.ServiceSynchronizationType = ServiceSynchronizationType.Synchronous;//Default

            // Reconcile
            ReconcileResult reconcileResult = currentVersion.Reconcile(reconcileOptions, postOptions);
            if (reconcileResult.HasConflicts)
            {
                //TODO resolve conflicts

            }

        }
    }
}

// Partial posting allows developers to post a subset of changes made in a version.
// One sample use case is an electric utility that uses a version to design the facilities in
// a new housing subdivision. At some point in the process, one block of new houses have been
// completed, while the rest of the subdivision remains unbuilt.  Partial posting allows the user
// to post the completed work, while leaving not yet constructed features in the version to be
// posted later. Partial posting requires a branch-versioned feature service using ArcGIS
// Enterprise 10.9 and higher

// Specify a set of features that were constructed
QueryFilter constructedFilter = new QueryFilter()
{
    WhereClause = "ConstructedStatus = 'True'"
};
// This selection represents the inserts and updates to the support
// structure feature class that we wish to post
using (Selection constructedSupportStructures = supportStructureFeatureClass.Select(constructedFilter, SelectionType.ObjectID, SelectionOption.Normal))
{
    // Specifying which feature deletions you wish to post is slightly trickier, since you cannot issue
    // a query to fetch a set of deleted features Instead, a list of ObjectIDs must be used
    using (Selection deletedSupportStructures = supportStructureFeatureClass.Select(
                                        null, SelectionType.ObjectID, SelectionOption.Empty))
    {
        deletedSupportStructures.Add(deletedSupportStructureObjectIDs);  //deletedSupportStructureObjectIDs is
                                                                         //defined as List<long>

        //Perform the reconcile with partial post
        //At 2.x - 
        //ReconcileDescription reconcileDescription = new ReconcileDescription();
        //reconcileDescription.ConflictDetectionType = ConflictDetectionType.ByColumn;
        //reconcileDescription.ConflictResolutionMethod = ConflictResolutionMethod.Continue;
        //reconcileDescription.ConflictResolutionType = ConflictResolutionType.FavorEditVersion;
        //reconcileDescription.PartialPostSelections = new List<Selection>() { constructedSupportStructures, deletedSupportStructures };
        //reconcileDescription.WithPost = true;

        //ReconcileResult reconcileResult = designVersion.Reconcile(reconcileDescription);

        ReconcileOptions reconcileOptions = new ReconcileOptions();//reconcile against Default
        reconcileOptions.ConflictDetectionType = ConflictDetectionType.ByColumn;
        reconcileOptions.ConflictResolutionMethod = ConflictResolutionMethod.Continue;
        reconcileOptions.ConflictResolutionType = ConflictResolutionType.FavorEditVersion;

        PostOptions postOptions = new PostOptions();//post against Default
        postOptions.PartialPostSelections = new List<Selection>() {
              constructedSupportStructures, deletedSupportStructures };
        postOptions.ServiceSynchronizationType = ServiceSynchronizationType.Synchronous;

        ReconcileResult reconcileResult = designVersion.Reconcile(reconcileOptions, postOptions);

        //TODO process result(s)
    }
}