Adapts a homogeneous stream of one kind to another, using converter
(by default identityPayloadConverter, which rejects a kind change). When
fromKind === toKind the stream is passed straight through untouched (no
per-item work at all). This is the ONE place a kind mismatch is decided -
once per stream, not once per item.
Adapts a homogeneous stream of one kind to another, using
converter(by default identityPayloadConverter, which rejects a kind change). WhenfromKind === toKindthe stream is passed straight through untouched (no per-item work at all). This is the ONE place a kind mismatch is decided - once per stream, not once per item.