Writer means that you are the author of the story or vignetee or a written piece of work etc. A reader means that you are the person reading the story, book, poem, etc.
together in collaboration
When a writer expects a reader to fill in the gaps, he or she is expecting the reader to compress.
A persuasive writer has to catch the attention of the reader, make his case by presenting the for and against and be able to convince the reader after he finishes reading his work.
To discover whether the writer of the work had bias about the subject
When a writer expects the reader to fill in the gaps, he or she is expecting the reader to compress.
Context
I read it. But 'reader' means 'writer'. The Writer is Mark Twain
Writer's style is their unique way of speaking to the reader. Each writer has their own style.
A book connects the reader and the writer by allowing the writer's thoughts, ideas, and stories to come alive in the reader's imagination. Through the words on the pages, the writer can share their experiences, insights, and emotions with the reader, creating a unique bond that transcends time and space. This connection is formed through the reader's interpretation and engagement with the text, which brings the writer's words to life in their own mind.
The heart of a writer's message is that portion of his writing that is most meaningful to him and his reader. Of course, the theme, spirit and lesson of the writing will differ from reader to reader. But the heart will always be the part that is most important and meaningful for a writer to convey.
"What is the writer trying to get me to think about..."
Technical writing can read like its writer knows more than the reader. This denies the reader the dignity the reader has earned. To avoid this, a technical writer can write as though the writer sits at the reader's elbow offering kind guidance. The writer can write in the third-person, in the present tense and in an active voice. This can help the reader preserve his or her dignity.