             }
         }
 
+        /// Appends parameter to `Builder`
+        /// - returns: New `Builder` with same properties as receiver but with appended parameter
         public func appending(parameterValue value: Parameters.Value, for key: Parameters.Key) -> Builder {
             return appending(parameters: [key: value])
         }
 
+        /// Assigns parameter encoding to `Builder`
+        /// - throws: `Error.reassignProperty(name: "parameterEncoding")` if parameter encoding was previously assigned.
+        /// - returns: New `Builder` with same properties as receiver but with assigned parameter encoding
         public func with(parameterEncoding: ParameterEncoding) throws -> Builder {
             guard self.parameterEncoding == nil else {
                 throw Error.reassignProperty(name: "parameterEncoding")

}

extension HTTPRequestData {
    public struct Builder {

        public static var baseURL: URL!

        private let url: URL


import Foundation

///Represents values passed to HTTP request
public struct HTTPRequestData {

    public typealias HeaderFields = [String: String]
