resize

        # IO::Buffer.resize

(from ruby core)
### Implementation from Buffer
---
    resize(new_size) -> self

---

Resizes a buffer to a `new_size` bytes, preserving its content.
Depending on the old and new size, the memory area associated with the
buffer might be either extended, or rellocated at different address with
content being copied.

    buffer = IO::Buffer.new(4)
    buffer.set_string("test", 0)
    buffer.resize(8) # resize to 8 bytes
    #  =>
    # #<IO::Buffer 0x0000555f5d1a1630+8 INTERNAL>
    # 0x00000000  74 65 73 74 00 00 00 00                         test....

External buffer (created with ::for), and locked buffer can not be
resized.