Deserialises a basic_result from a std::istream.

Serialisation format is:

<unsigned int flags><space><value_type if set and not void><error_type if set and not void>

Overridable: Not overridable.

Requires: That operator>> is a valid expression for std::istream and T and E.

Namespace: BOOST_OUTCOME_V2_NAMESPACE

Header: <boost/outcome/iostream_support.hpp> (must be explicitly included manually).