GET errors after partial data #4075

what is the difference b/w returning a status error from InitGetObjectStream and returning a status from the reader later?

Originally posted by @carpawell in #4067

i propose to review all GET code on the topic of reaction to a status error following some non-empty data. Currently, GET stream can end with any status. But this is not valid in all cases

there are 3 normal results:

1. everything is OK: server streams [header] + [payload] with OK status in all response messages
2. object is unavailable (not found, removed, etc.): server responds with corresponding status with no data
3. stream cannot be finished: server responds with INTERNAL or CONTEXT status

usually client or proxy node just pipes data as it goes

but some cases can be confusing. For example:

1. header is received
2. several chunks are received, but not all
3. 404/removed/other status

in these cases, when SN is a client working w/ container placement generally including multiple servers, it should abort the stream. For normal cases above, SN can memorize the progress and continue w/ reserve server