CommonFormatter - make it streamable¶
make Formatter streamable
optionally adjust users
The current Formatter interface accumulates everything in an in-memory buffer (or buffers, even), which makes it unusable in cases where we are dumping/formatter large amounts of memory (e.g., a significant portion of the allocate memory). We should make an alternative interface that lets you specify an ostream for the Formatter and emits output as it goes (instead of appending to the buffer).
there is also an ostream stream_buf in tree; see https://github.com/ceph/ceph/blob/master/src/common/PrebufferedStreambuf.h