B64Decode - base64 decode.

B64Encode - base64 encode.

Comprehension - remove blank strings in slices.

GetCallFuncName - get the function name of the caller.

GetCallFuncRoute - get the route to the function name of the caller and return it as a slice.

ParseEvents - extract `[]*linebot.Event`.

RandomString - generate a random string.

SetGinContext - create `*gin.Context` from `http.ResponseWriter` and `*http.Request`.

ValidateSignature - perform signature verification.