Burger's Daughter by Nadine Gordimer can be seen as a postcolonial text in that it provides a platform for postcolonial discourse through the character of Zwelinzima, who grew up alongside Rosa in her parents' house.
When Zwelinzima was a child, he was known as Baasie. Rosa's parents treated him as if he were their own son. Rosa's mother and father were staunch Communists and opponents of apartheid. As such, they regarded all human beings as equal.
However, when Zwelinzima catches up with Rosa years later, he has some pretty harsh words for her parents. With these words, he expresses an attitude commensurate with postcolonial discourse.
He tells Rosa that he resents the way in which her parents deprived him of his culture and from knowing other Black South Africans. Though they were undoubtedly well-meaning, they were also inadvertently showing themselves to be white paternalists in cutting Zwelinzima off from his own people and his own heritage.
At the heart of postcolonialism is the idea that those previously oppressed and silenced by colonialism need to find their own voice, to tell their own stories, and to speak their truths. In criticizing his adoptive parents and the way that they deprived him of his own culture and his own people, and in firmly asserting his identity as a Black South African, Zwelinzima is the living embodiment of that idea.