feat(IObjectApi): add StatAsync, closes #92

src/CoreApi/IObjectApi.cs

@@ -66,6 +66,21 @@ public interface IObjectApi
         /// </returns>
         Task<DagNode> GetAsync(Cid id, CancellationToken cancel = default(CancellationToken));
 
+        /// <summary>
+        ///   Information on a MerkleDag node.
+        /// </summary>
+        /// <param name="id">
+        ///   The <see cref="Cid"/> of the node.
+        /// </param>
+        /// <param name="cancel">
+        ///   Is used to stop the task.  When cancelled, the <see cref="TaskCanceledException"/> is raised.
+        /// </param>
+        /// <returns>
+        ///    A task that represents the asynchronous operation. The task's value
+        ///    contains the <see cref="ObjectStat"/>.
+        /// </returns>
+        Task<ObjectStat> StatAsync(Cid id, CancellationToken cancel = default(CancellationToken));
+
         /// <summary>
         ///   Store a MerkleDAG node.
         /// </summary>

src/CoreApi/ObjectStat.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Ipfs.CoreApi
+{
+    /// <summary>
+    ///   Information on a DAG node.
+    /// </summary>
+    /// <seealso cref="IObjectApi"/>
+    public class ObjectStat
+    {
+        /// <summary>
+        ///   Number of links.
+        /// </summary>
+        public int LinkCount { get; set; }
+
+        /// <summary>
+        ///   Size of the links segment.
+        /// </summary>
+        public long LinkSize { get; set; }
+
+        /// <summary>
+        ///   Size of the raw, encoded data.
+        /// </summary>
+        public long BlockSize { get; set; }
+
+        /// <summary>
+        ///   Siz of the data segment.
+        /// </summary>
+        public long DataSize { get; set; }
+
+        /// <summary>
+        ///   Size of object and its references
+        /// </summary>
+        public long CumulativeSize { get; set; }
+    }
+}