Note: to remove this source, call .removeSource() on the resulting WriteBusSource
Creates another Observer such that calling its onNext will call this observer's onNext with the same value, but only if it passes the test.
Creates another Observer such that calling its onNext will call this observer's onNext
with the value processed by the project
function.
Creates another Observer such that calling its onNext will call this observer's onNext
with the value processed by the project
function.
This is useful when you need to pass down an Observer[A] to a child component
which should not know anything about the type A, but both child and parent know
about type B
, and the parent knows how to translate B into A.