     ///
     /// - returns: The builder instance.
     public func http() -> RequestBuilder {
-        return scheme("http")
+        return scheme(Scheme.http.rawValue)
     }
 
     /// Secure http.
     ///
     /// - returns: The builder instance.
     public func https() -> RequestBuilder {
-        return scheme("https")
+        return scheme(Scheme.https.rawValue)
     }
     
     // MARK: - HTTP Headers
     
-    /// <#Description#>
+    /// Sets a value-HTTP header pair.
     ///
-    /// - parameter value: <#value description#>
-    /// - parameter field: <#field description#>
+    /// - parameter value: The value to use for the header.
+    /// - parameter field: The header for which the value is being changed.
     public func setValue(_ value: String?,
                          for headerField: String) -> RequestBuilder {
         self.httpHeaders[headerField] = value

        
        //
        var request = URLRequest(url: (components?.url)!)
        request.httpMethod = httpMethod.rawValue
        request.allHTTPHeaderFields = httpHeaders
        
        return request


import Foundation

// MARK: - Convenience Constants

/// HTTP Method enumeration.
public enum HttpMethod: String {
    case GET, POST, PUT, DELETE
}

/// Schemes.
public enum Scheme: String {
    case http, https
}

// MARK: - Request builder

/// Request Builder.
///
