buf.WriteByte(testString[1])
		c, err := buf.ReadByte()
		if want := testString[1]; err != nil || c != want {
			t.Errorf("ReadByte: got (%q, %v), want (%q, %v)", c, err, want, nil)
		}
		c, err = buf.ReadByte()
		if err != io.EOF {
			t.Errorf("ReadByte: got (%q, %v), want (%q, %v)", c, err, byte(0), io.EOF)
		}
	}
}

		n = m
	}
	data := b.buf[b.off : b.off+n]
	b.off += n
	if n > 0 {
		b.lastRead = opRead
	}
	return data
}

// ReadByte reads and returns the next byte from the buffer.
// If no byte is available, it returns error [io.EOF].
func (b *Buffer) ReadByte() (byte, error) {
	if b.empty() {
		// Buffer is empty, reset to recover space.
		b.Reset()
		return 0, io.EOF
	}
	c := b.buf[b.off]