Fix nullability of Obj-C header manipulation

Fixes #67.

README.md

@@ -413,8 +413,10 @@ work by you shall be dual licensed as above, without any additional terms or con
 #### Development
 
 * Add Obj-C convenience functions for creating upload requests with an `NSData` but no explicit `contentType` ([#65][]).
+* Fix the Obj-C `-setValue:forHeaderField:` and `-setValue:forDefaultHeaderField:` methods to take a nullable value ([#67][]).
 
 [#65]: https://github.com/postmates/PMHTTP/issues/65 "Obj-C convenience functions for requests with data"
+[#67]: https://github.com/postmates/PMHTTP/issues/67 "Obj-C -[HTTPManagerRequest setValue:forHeaderField:] should take nullable value"
 
 #### v4.4.3 (2019-11-14)
 

Sources/ObjectiveC.swift

@@ -44,10 +44,10 @@ extension HTTPManager {
 
     /// Sets a specified default HTTP header field.
     ///
-    /// - Parameter value: The value for the header field.
+    /// - Parameter value: The value for the header field. If `nil` the header is deleted.
     /// - Parameter field: The name of the header field. Header fields are case-insensitive.
     @objc(setValue:forDefaultHeaderField:)
-    public func __objc_setValue(_ value: String, forDefaultHeaderField field: String) {
+    public func __objc_setValue(_ value: String?, forDefaultHeaderField field: String) {
         defaultHeaderFields[field] = value
     }
 
@@ -790,9 +790,9 @@ extension HTTPManagerRequest {
 
     /// Sets a specified HTTP header field.
     ///
-    /// - Parameter value: The value for the header field.
+    /// - Parameter value: The value for the header field. If `nil` the header is deleted.
     /// - Parameter field: The name of the header field. Header fields are case-insensitive.
-    @objc(setValue:forHeaderField:) public func __objc_setValue(_ value: String, forHeaderField field: String) {
+    @objc(setValue:forHeaderField:) public func __objc_setValue(_ value: String?, forHeaderField field: String) {
         headerFields[field] = value
     }