Credential is open to set anytime

Sources/DropboxFileProvider.swift

@@ -34,7 +34,7 @@ open class DropboxFileProvider: FileProviderBasicRemote {
     }
     
     open weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
+    open var credential: URLCredential?
     open private(set) var cache: URLCache?
     public var useCache: Bool
     public var validatingCache: Bool

Sources/FileProvider.swift

@@ -51,13 +51,13 @@ public protocol FileProviderBasic: class, NSCoding, NSSecureCoding {
      
      **Example initialization:**
      ````
-     let credential = URLCredential(user: "user", password: "password", persistence: .forSeession)
+     provider.credential = URLCredential(user: "user", password: "password", persistence: .forSeession)
      ````
      
      - Note: In OAuth based providers like `DropboxFileProvider` and `OneDriveFileProvider`, password is Token.
      use [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) library to fetch clientId and Token of user.
      */
-    var credential: URLCredential? { get }
+    var credential: URLCredential? { get set }
     
     /**
      Returns an Array of `FileObject`s identifying the the directory entries via asynchronous completion handler.

Sources/LocalFileProvider.swift

@@ -21,7 +21,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
     open var dispatch_queue: DispatchQueue
     open var operation_queue: OperationQueue
     open weak var delegate: FileProviderDelegate?
-    open internal(set) var credential: URLCredential?
+    open var credential: URLCredential?
     
     /// Underlying `FileManager` object for listing and metadata fetching.
     open private(set) var fileManager = FileManager()

Sources/OneDriveFileProvide.swift

@@ -33,7 +33,7 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
     }
     
     open weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
+    open var credential: URLCredential?
     open private(set) var cache: URLCache?
     public var useCache: Bool
     public var validatingCache: Bool

Sources/SMBFileProvider.swift

@@ -15,7 +15,7 @@ class SMBFileProvider: FileProvider, FileProviderMonitor {
     open var dispatch_queue: DispatchQueue
     open var operation_queue: OperationQueue
     open weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
+    open var credential: URLCredential?
     
     public typealias FileObjectClass = FileObject
     

Sources/WebDAVFileProvider.swift

@@ -32,7 +32,11 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
     }
     
     public weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
+    open var credential: URLCredential? {
+        didSet {
+            sessionDelegate?.credential = credential
+        }
+    }
     open private(set) var cache: URLCache?
     public var useCache: Bool
     public var validatingCache: Bool