Add documentation for createBoundary helper.

Author: octet-stream

lib/index.ts

@@ -4,4 +4,3 @@ export * from "./Encoder"
 
 export {default as isFileLike} from "./util/isFile"
 export {default as isFormDataLike} from "./util/isFormData"
-export {default as createBoundary} from "./util/createBoundary"

lib/util/createBoundary.ts

@@ -3,6 +3,8 @@ const alphabet
 
 /**
  * Generates a boundary string for FormData encoder.
+ *
+ * @param size The size of the resulting string
  */
 function createBoundary(size: number): string {
   let res = ""