Create a new modifiable buffer from an existing buffer.

mutable_buffers_1 buffer(
    const mutable_buffer & b,
    std::size_t max_size_in_bytes);

Return Value

A mutable_buffers_1 value equivalent to:

mutable_buffers_1(
    buffer_cast<void*>(b),
    min(buffer_size(b), max_size_in_bytes));