Types for all Netsys modules
Remember that up to OCaml-4.01 there was only the string type, and strings were mutable (although frequently used as if there were immutable). Since OCaml-4.02 there is the immutable string and the mutable bytes type.
The general strategy for switching to the string/bytes scheme is to replace string everywhere with bytes, and to provide additional functions taking strings as input or output where it makes sense. There are exceptions, though, e.g. when the string acts as a key in a data structure.
The type name "string" also occurs in function names (e.g. "get_string") and in variant names (e.g. String_case). As we want to be backward compatible, we keep the old names for functions on bytes, and mark them as deprecated.
A tagged buffer. Note that the `String case is deprecated, and only provided for backward compatibility.
A tagged string which is considered as immutable. See also the support module Netstring_tstring.