diff --git a/Source/Network/Client.swift b/Source/Network/Client.swift
index 589ceb8..0366d10 100644
--- a/Source/Network/Client.swift
+++ b/Source/Network/Client.swift
@@ -20,7 +20,7 @@ public protocol Client<Request, Response> {
         header: ClientHeader,
         body: Request,
         timeout: Interval?,
-        optionBlock: (inout URLRequest) -> Void
+        optionBlock: @escaping (inout URLRequest) -> Void
     ) -> Promise<ClientResult<Response>, Error>
 }
 
@@ -30,7 +30,7 @@ extension Client {
         method: ClientMethod = .get,
         header: ClientHeader = [:],
         timeout: Interval? = nil,
-        optionBlock: (inout URLRequest) -> Void = { _ in }
+        optionBlock: @escaping (inout URLRequest) -> Void = { _ in }
     ) -> Promise<ClientResult<Response>, Error> where RequestValue? == Request {
         request(
             url: url,
@@ -48,7 +48,7 @@ extension Client {
         header: ClientHeader = [:],
         body: Request,
         timeout: Interval? = nil,
-        optionBlock: (inout URLRequest) -> Void = { _ in }
+        optionBlock: @escaping (inout URLRequest) -> Void = { _ in }
     ) -> Promise<ClientResult<Response>, Error> {
         request(
             url: url,
diff --git a/Source/Network/Implement/Client/DataClient.swift b/Source/Network/Implement/Client/DataClient.swift
index ac30a35..4a5199c 100644
--- a/Source/Network/Implement/Client/DataClient.swift
+++ b/Source/Network/Implement/Client/DataClient.swift
@@ -39,7 +39,7 @@ extension DataClient {
         header: ClientHeader = [:],
         body: Data? = nil,
         timeout: Interval? = nil,
-        optionBlock: (inout URLRequest) -> Void = { _ in }
+        optionBlock: @escaping (inout URLRequest) -> Void = { _ in }
     ) -> Promise<ClientResult<Data?>, Error> {
         let pending = Promise<ClientResult<Data?>, Error>.pending()
         
diff --git a/Source/Network/Implement/Client/JSONClient.swift b/Source/Network/Implement/Client/JSONClient.swift
index 57d4a5e..2201c0a 100644
--- a/Source/Network/Implement/Client/JSONClient.swift
+++ b/Source/Network/Implement/Client/JSONClient.swift
@@ -36,7 +36,7 @@ extension JSONClient {
         header: ClientHeader = [:],
         body: JSON? = nil,
         timeout: Interval? = nil,
-        optionBlock: (inout URLRequest) -> Void = { _ in }
+        optionBlock: @escaping (inout URLRequest) -> Void = { _ in }
     ) -> Promise<ClientResult<JSON>, Error> {
         let header = header.merging([
             "Content-Type": "application/json"