add documentations for DXFeed

DXFeedFramework/Api/DXFeed.swift

@@ -7,25 +7,40 @@
 
 import Foundation
 
+/// Main entry class for dxFeed API.
+///
+/// [Read it first Javadoc](https://docs.dxfeed.com/dxfeed/api/com/dxfeed/api/DXFeed.html)
 public class DXFeed {
+    /// Feed native wrapper.
     private let native: NativeFeed
-    private var attachedSubscriptions = ConcurrentSet<DXFeedSubcription>()
 
     deinit {
     }
-
+    
     internal init(native: NativeFeed?) throws {
         if let native = native {
             self.native = native
         } else {
             throw NativeException.nilValue
         }
     }
-
+    /// Creates new subscription for a list of event types that is attached to this feed.
+    ///
+    /// [Javadoc](https://docs.dxfeed.com/dxfeed/api/com/dxfeed/api/DXFeed.html#createSubscription-java.lang.Class)
+    /// - Parameters:
+    ///     - events: The list of event codes.
+    /// - Returns: ``DXFeedSubcription``
+    /// - Throws: GraalException. Rethrows exception from Java.
     public func createSubscription(_ events: [EventCode]) throws -> DXFeedSubcription {
         return try DXFeedSubcription(native: native.createSubscription(events), events: events)
     }
-
+    /// Creates new subscription for a one event type that is attached to this feed.
+    ///
+    /// [Javadoc](https://docs.dxfeed.com/dxfeed/api/com/dxfeed/api/DXFeed.html#createSubscription-java.lang.Class)
+    /// - Parameters:
+    ///     - event: event code
+    /// - Returns: ``DXFeedSubcription``
+    /// - Throws: GraalException. Rethrows exception from Java.
     public func createSubscription(_ event: EventCode) throws -> DXFeedSubcription {
         return try DXFeedSubcription(native: native.createSubscription(event), events: [event])
     }