-add cached `token` to Contact objects to minimize findValue requests
-remove self_store, always store to remote contacts even if we're the closest known node to the hash
-move the store call and error handling from announceHaveBlob to a smaller function of its own
-track contact failures, last replied, and last requested. use this to provide a 'contact_is_good' property on Contact objects
-ensure no duplicate contact objects are created
-remove confusing conflation of node id strings with Contact objects, update docstrings
-move RPC failure tracking to a callback/errback pair in sendRPC (so the contact is only updated once)
-handle seed nodes during the join sequence by setting their node ids after they initially reply to our ping
-name all of the kademlia RPC keyword args, remove confusing **kwargs and dictionary parsing
-add host ip/port to DHT send/receive logging to make the results comprehensible when running many nodes at once
-remove hash_announcer from Node and DiskBlobManager
-remove announcement related functions from DiskBlobManager
-update SQLiteStorage to store announcement times and provide blob hashes needing to be announced
-use dataExpireTimeout from lbrynet.dht.constants for re-announce timing
-use DeferredSemaphore for concurrent blob announcement
-adds reactor (clock) and reactor functions listenUDP, callLater, and resolve as arguments to Node.__init__
-set the reactor clock on LoopingCalls to make them easily testable
-convert callLater manage loops to LoopingCalls
-use looping call for running manage function rather than a scheduled
callLater
-track announce speed
-retry store requests that failed up to 3 times
-return a dict of {blob_hash: [storing_node_id]} results from
_announce_hashes
_refreshRoutingTable inline cb refactor
-add and use DeferredLockContextManager
-don't trap errback from iterativeFindNode in iterativeAnnounceHaveBlob
This method can be used by other components to check
if in the Node routing table there is at least one peer.
Signed-off-by: Antonio Quartulli <antonio@mandelbit.com>