Optionalproperties: Partial<{}>StaticinitStaticnextYields the next name/value pair in the MessageHeaders being
iterated by iter.
If iter has already yielded the last header, then
MessageHeadersIter.next will return false and name and value
will be unchanged.
An opaque type used to iterate over a MessageHeaders structure
After intializing the iterator with MessageHeadersIter.init, call MessageHeadersIter.next to fetch data from it.
You may not modify the headers while iterating over them.