Sippet.Message.update_header

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update_header(message, header, initial \\ nil, fun)

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Specs

update_header(t(), header(), value() | nil, (value() -> value())) :: t()

Updates the header in message with the given function.

If header is present in message with value value, fun is invoked with argument value and its result is used as the new value of header. If header is not present in message, initial is inserted as the value of header.