Partial Match Completion
Complete anything by typing just parts of the identifier.
GoLand provides completion suggestions when you typed only a part of a word (any part, even characters from somewhere in the middle).
Also, case-insensitive CamelHump completion is supported, so you can just type the capital letters along with a number of subsequent characters. For example, type ReWrCl to get io.ReadWriteCloser.
Works automatically, you don't have to do anything.