`normalizeMethodName` reflectively accessed the RequestMethod enum. With a smart
optimizer, properties from the enum could be removed or renamed, and so user
code just passing in e.g. 'PATCH' might not work. This change fixes the code to
be more explicit and avoids the optimizer issue.
BREAKING CHANGE:
Exceptions are no longer part of the public API. We don't expect that anyone should be referring to the Exception types.
ExceptionHandler.call(exception: any, stackTrace?: any, reason?: string): void;
change to:
ErrorHandler.handleError(error: any): void;
